Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Stefan Monnier]

> -The @samp{To}, @samp{Cc}, and @samp{Bcc} fields can appear any number
> +The @samp{To}, @samp{CC}, and @samp{BCC} fields can appear any number

FWIW, I can't remember seeing "CC:" or "BCC:" in an email message
whereas I've seen "Cc:" and "Bcc:" many many times.  So my reaction to
the above line would be "Huh?  Why didn't they write `TO` to
be consistent?"

I understand "CC" arose as an initialism whereas "To" is a word, but
nowadays I consider the "Cc" of my email messages to be a word more than
an initialism (IOW it means "CC" more than it means "Carbon Copy").


        Stefan

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Andreas Schwab]

On Mai 20 2018, Stefan Monnier <monnier@IRO.UMontreal.CA> wrote:

>> -The @samp{To}, @samp{Cc}, and @samp{Bcc} fields can appear any number
>> +The @samp{To}, @samp{CC}, and @samp{BCC} fields can appear any number
>
> FWIW, I can't remember seeing "CC:" or "BCC:" in an email message
> whereas I've seen "Cc:" and "Bcc:" many many times.  So my reaction to
> the above line would be "Huh?  Why didn't they write `TO` to
> be consistent?"

Also, RFC 2822 always uses the capitalized form (the only exception is
Message-ID).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: emacs-devel@gnu.org
> Date: Sun, 20 May 2018 09:47:45 -0400
> 
> > -The @samp{To}, @samp{Cc}, and @samp{Bcc} fields can appear any number
> > +The @samp{To}, @samp{CC}, and @samp{BCC} fields can appear any number
> 
> FWIW, I can't remember seeing "CC:" or "BCC:" in an email message

I see them all the time.  I guess it depends on your MUA.

> I understand "CC" arose as an initialism whereas "To" is a word, but
> nowadays I consider the "Cc" of my email messages to be a word more than
> an initialism (IOW it means "CC" more than it means "Carbon Copy").

Well, I beg to differ.

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Paul Eggert]

[-- Attachment #1: Type: text/plain, Size: 1143 bytes --]

 > From: Eli Zaretskii <eliz@gnu.org>
 > To: Stefan Monnier <monnier@IRO.UMontreal.CA>
 > ...
 > Cc: emacs-devel@gnu.org
 > ...
> I see them all the time.  I guess it depends on your MUA.

It's typically "Cc" and "Bcc" in email contexts, because of Internet RFC 5322 
and its predecessors. Although these standards are case-insensitive, the usual 
spelling in email headers is "Cc:" etc.

The abbreviation "cc" was not originally an initialism. It meant two or more 
copies, from the Latin abbreviations "c" for "copia" and "cc" for "copiae". By 
the same tradition "pp" (for "paginae") is still widely used in English. 
Although "cc" has also come to mean "carbon copy", that's a reuse of the Latin. 
In traditional English-language business correspondence over the years I have 
seen "cc" most often, though I have also seen "CC" and "Cc" quite a bit.

Since "CC" also stands for "CC Mode", "Creative Commons" and suchlike, it's 
useful for Emacs to stick with the RFC 5322 capitalization to distinguish email 
Cc from the other CC usages. I installed the attached into master to try to be 
more consistent about this.

[-- Attachment #2: 0001-Use-Cc-for-email-copies-as-per-RFC-5322.txt --]
[-- Type: text/plain, Size: 53253 bytes --]

From ee2916c6d25f963649c9fe2583faf66538f60180 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sun, 20 May 2018 10:47:32 -0700
Subject: [PATCH] =?UTF-8?q?Use=20=E2=80=9CCc=E2=80=9D=20for=20email=20copi?=
 =?UTF-8?q?es,=20as=20per=20RFC=205322.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Also fix similar problems with Bcc, Fcc, In-Reply-To,
and similar email headers.  See thread starting at:
https://lists.gnu.org/r/emacs-devel/2018-05/msg00463.html
---
 admin/notes/bugtracker          | 26 ++++++++---------
 doc/emacs/ChangeLog.1           |  2 +-
 doc/emacs/rmail.texi            | 12 ++++----
 doc/emacs/sending.texi          | 20 ++++++-------
 doc/misc/efaq.texi              | 14 +++++-----
 doc/misc/emacs-mime.texi        |  2 +-
 doc/misc/gnus-faq.texi          | 18 ++++++------
 doc/misc/gnus.texi              |  4 +--
 doc/misc/message.texi           |  8 +++---
 doc/misc/mh-e.texi              |  4 +--
 etc/NEWS.18                     |  4 +--
 etc/NEWS.19                     |  4 +--
 etc/NEWS.20                     |  2 +-
 etc/refcards/cs-survival.tex    |  2 +-
 etc/refcards/fr-survival.tex    |  2 +-
 etc/refcards/sk-survival.tex    |  2 +-
 etc/refcards/survival.tex       |  2 +-
 lisp/ChangeLog.2                |  4 +--
 lisp/ChangeLog.4                |  2 +-
 lisp/ChangeLog.5                |  2 +-
 lisp/ChangeLog.7                |  2 +-
 lisp/gnus/gnus-art.el           | 14 +++++-----
 lisp/gnus/gnus-msg.el           |  4 +--
 lisp/gnus/message.el            | 12 ++++----
 lisp/mail/feedmail.el           |  4 +--
 lisp/mail/mail-utils.el         |  2 +-
 lisp/mail/mailabbrev.el         |  6 ++--
 lisp/mail/mailalias.el          |  6 ++--
 lisp/mail/rfc2047.el            |  2 +-
 lisp/mail/rmail-spam-filter.el  |  2 +-
 lisp/mail/rmail.el              |  8 +++---
 lisp/mail/rmailsum.el           |  2 +-
 lisp/mail/sendmail.el           | 62 ++++++++++++++++++++---------------------
 lisp/mail/smtpmail.el           | 18 ++++++------
 lisp/mail/uce.el                |  2 +-
 lisp/mh-e/mh-comp.el            |  2 +-
 lisp/mh-e/mh-show.el            |  2 +-
 lisp/obsolete/mailpost.el       |  4 +--
 test/lisp/gnus/message-tests.el |  4 +--
 39 files changed, 147 insertions(+), 147 deletions(-)

diff --git a/admin/notes/bugtracker b/admin/notes/bugtracker
index c394581..f3bc304 100644
--- a/admin/notes/bugtracker
+++ b/admin/notes/bugtracker
@@ -8,7 +8,7 @@ This is 95% of all you will ever need to know.
 
 ** How do I report a bug?
 Use M-x report-emacs-bug, or send mail to bug-gnu-emacs@gnu.org.
-If you want to Cc someone, use an "X-Debbugs-CC" header (or
+If you want to Cc someone, use an "X-Debbugs-Cc" header (or
 pseudo-header, see below) instead.
 
 ** How do I comment on a bug?
@@ -53,7 +53,7 @@ i) Your report will be assigned a number and generate an automatic reply.
 ii) Optionally, you can set some database parameters when you first
 report a bug (see "Setting bug parameters" below).
 
-iii) If you want to CC: someone, use X-Debbugs-CC: (note this only
+iii) If you want to Cc someone, use X-Debbugs-Cc: (note this only
 applies to _new_ reports, not followups).
 
 Once your report is filed and assigned a number, it is sent out to the
@@ -64,8 +64,8 @@ quiet@debbugs.gnu.org.
 ** How do I reply to an existing bug report?
 Reply to 123@debbugs.gnu.org, replacing 123 with the number
 of the bug you are interested in.  NB this only sends mail to the
-bug-list, it does NOT send a CC to the original bug submitter.
-So you need to explicitly CC him/her (and anyone else you like).
+bug-list, it does NOT send a Cc to the original bug submitter.
+So you need to explicitly Cc him/her (and anyone else you like).
 (This works the same way as all the Emacs mailing lists.  We generally
 don't assume anyone who posts to a list is subscribed to it, so we
 cc everyone on replies.)
@@ -95,23 +95,23 @@ normal bug reporting.)
 
 ** When reporting a new bug, to send a Cc to another address
 (e.g. bug-cc-mode@gnu.org), do NOT just use a Cc: header.
-Instead, use "X-Debbugs-CC:".  This ensures the Cc address(es) will get a
+Instead, use "X-Debbugs-Cc:".  This ensures the Cc address(es) will get a
 mail with the bug report number in.  If you do not do this, each reply
 in the subsequent discussion might end up creating a new bug.
 This is annoying.  (So annoying that a form of message-id tracking has
 been implemented to hopefully stop this happening, but it is still
-better to use X-Debbugs-CC.)
+better to use X-Debbugs-Cc.)
 
 If you want to send copies to more than one address, add them
-comma-separated in only one X-Debbugs-CC line.
+comma-separated in only one X-Debbugs-Cc line.
 
 Like any X-Debbugs- header, this one can also be specified in the
 pseudo-header (see below), if your mail client does not let you add
 "X-" headers.
 
-If a new report contains X-Debbugs-CC in the input, this is
+If a new report contains X-Debbugs-Cc in the input, this is
 converted to a real Cc header in the output.  (See Bug#1780,5384)
-It is also merged into the Resent-CC header (see below).
+It is also merged into the Resent-Cc header (see below).
 
 ** How does Debbugs send out mails?
 
@@ -120,15 +120,15 @@ header is unchanged.  In new reports only (at present), the To:
 address is altered as follows.  Any "bug-gnu-emacs",
 "emacs-pretest-bug", or "submit@debbugs" address is replaced by
 123@debbugs in the mail that gets sent out.  (This also applies to any
-Cc: header, though you should be using X-Debbugs-CC instead in new
+Cc: header, though you should be using X-Debbugs-Cc instead in new
 reports).  The original header is stored as X-Debbugs-Original-To, if
-it was changed.  Any X-Debbugs-CC is merged into the Cc.
+it was changed.  Any X-Debbugs-Cc is merged into the Cc.
 
 Mails arriving at the bug list have the following Resent-* headers:
 
 Resent-From: person who submitted the bug
 Resent-To:   owner@debbugs.gnu.org
-Resent-CC:   maintainer email address, plus any X-Debbugs-CC: entries
+Resent-Cc:   maintainer email address, plus any X-Debbugs-Cc: entries
 
 The "maintainer email address" is "bug-gnu-emacs@gnu.org" in most cases.
 
@@ -239,7 +239,7 @@ The control server ignores anything after the last line above.  So you
 can place control commands at the beginning of a reply to a bug
 report, and Bcc: the control server (note the commands have no effect
 if you just send them to the bug-report number).  Bcc: is better than Cc:
-in case people use Reply-to-All in response.
+in case people use Reply-To-All in response.
 
 Some useful control commands:
 
diff --git a/doc/emacs/ChangeLog.1 b/doc/emacs/ChangeLog.1
index ab9da47..26a0d3e 100644
--- a/doc/emacs/ChangeLog.1
+++ b/doc/emacs/ChangeLog.1
@@ -4398,7 +4398,7 @@
 	mail-header-separator.
 	(Mail Headers): Put info about initialization and changing in one place
 	at the start.  Update FCC section for mbox Rmail.  Clarify From
-	section, mention mail-setup-with-from.  Clarify Reply-to section.
+	section, mention mail-setup-with-from.  Clarify Reply-To section.
 	Add Mail-followup-to and mail-mailing-lists.  Clarify References
 	section.
 	(Mail Aliases): Update example, make less contentious.
diff --git a/doc/emacs/rmail.texi b/doc/emacs/rmail.texi
index 0a8bf7c..5bf96db 100644
--- a/doc/emacs/rmail.texi
+++ b/doc/emacs/rmail.texi
@@ -753,24 +753,24 @@ Rmail Reply
 to the message you are reading.  To do this, type @kbd{r}
 (@code{rmail-reply}).  This displays a mail composition buffer in
 another window, much like @kbd{C-x 4 m}, but preinitializes the
-@samp{Subject}, @samp{To}, @samp{CC}, @samp{In-reply-to} and
+@samp{Subject}, @samp{To}, @samp{Cc}, @samp{In-Reply-To} and
 @samp{References} header fields based on the message you are replying
 to.  The @samp{To} field starts out as the address of the person who
-sent the message you received, and the @samp{CC} field starts out with
+sent the message you received, and the @samp{Cc} field starts out with
 all the other recipients of that message.
 
 @vindex mail-dont-reply-to-names
   You can exclude certain recipients from being included automatically
 in replies, using the variable @code{mail-dont-reply-to-names}.  Its
 value should be a regular expression; any recipients that match are
-excluded from the @samp{CC} field.  They are also excluded from the
+excluded from the @samp{Cc} field.  They are also excluded from the
 @samp{To} field, unless this would leave the field empty.  If this
 variable is @code{nil}, then the first time you compose a reply it is
 initialized to a default value that matches your own address.
 
   To reply only to the sender of the original message, enter
 the reply command with a numeric argument: @kbd{C-u r} or @kbd{1 r}.
-This omits the @samp{CC} field completely for a particular reply.
+This omits the @samp{Cc} field completely for a particular reply.
 
   Once the mail composition buffer has been initialized, editing and
 sending the mail goes as usual (@pxref{Sending Mail}).  You can edit
@@ -939,8 +939,8 @@ Rmail Make Summary
   @kbd{C-M-r @var{rcpts} @key{RET}} (@code{rmail-summary-by-recipients})
 makes a partial summary mentioning only the messages that have one or
 more recipients matching the regular expression @var{rcpts}.  This is matched
-against the @samp{To}, @samp{From}, and @samp{CC} headers (supply a prefix
-argument to exclude the @samp{CC} header).
+against the @samp{To}, @samp{From}, and @samp{Cc} headers (supply a prefix
+argument to exclude the @samp{Cc} header).
 
 @kindex C-M-t @r{(Rmail)}
 @findex rmail-summary-by-topic
diff --git a/doc/emacs/sending.texi b/doc/emacs/sending.texi
index b7bdd69..720f747 100644
--- a/doc/emacs/sending.texi
+++ b/doc/emacs/sending.texi
@@ -170,14 +170,14 @@ Mail Headers
 Emacs updates it accordingly.  To specify more than one file, use
 several @samp{Fcc} fields, with one file name in each field.
 
-@item Reply-to
+@item Reply-To
 An address to which replies should be sent, instead of @samp{From}.
 This is used if, for some reason, your @samp{From} address cannot
 receive replies.
 
-@item Mail-reply-to
-This field takes precedence over @samp{Reply-to}.  It is used because
-some mailing lists set the @samp{Reply-to} field for their own
+@item Mail-Reply-To
+This field takes precedence over @samp{Reply-To}.  It is used because
+some mailing lists set the @samp{Reply-To} field for their own
 purposes (a somewhat controversial practice).
 
 @item Mail-Followup-To
@@ -186,14 +186,14 @@ Mail Headers
 mailing list that you are subscribed to, and want replies to go to the
 list without sending an extra copy to you.
 
-@item In-reply-to
+@item In-Reply-To
 An identifier for the message you are replying to.  Most mail readers
 use this information to group related messages together.  Normally,
 this header is filled in automatically when you reply to a message in
 any mail program built into Emacs.
 
 @item References
-Identifiers for previous related messages.  Like @samp{In-reply-to},
+Identifiers for previous related messages.  Like @samp{In-Reply-To},
 this is normally filled in automatically for you.
 @end table
 
@@ -220,12 +220,12 @@ Mail Headers
   You can direct Emacs to insert certain default headers into the mail
 buffer by setting the variable @code{mail-default-headers} to a
 string.  Then @kbd{C-x m} inserts this string into the message
-headers.  For example, here is how to add a @samp{Reply-to} and
+headers.  For example, here is how to add a @samp{Reply-To} and
 @samp{Fcc} header to each message:
 
 @smallexample
 (setq mail-default-headers
-      "Reply-to: foo@@example.com\nFcc: ~/Mail/sent")
+      "Reply-To: foo@@example.com\nFcc: ~/Mail/sent")
 @end smallexample
 
 @noindent
@@ -293,7 +293,7 @@ Mail Aliases
   Mail aliases expand as abbrevs---that is to say, as soon as you type
 a word-separator character after an alias (@pxref{Abbrevs}).  This
 expansion takes place only within the @samp{To}, @samp{From},
-@samp{Cc}, @samp{Bcc}, and @samp{Reply-to} header fields (plus their
+@samp{Cc}, @samp{Bcc}, and @samp{Reply-To} header fields (plus their
 @samp{Resent-} variants); it does not take place in other header
 fields, such as @samp{Subject}.
 
@@ -422,7 +422,7 @@ Header Editing
 @item C-c C-f C-b
 Move to the @samp{Bcc} header (@code{message-goto-bcc}).
 @item C-c C-f C-r
-Move to the @samp{Reply-to} header (@code{message-goto-reply-to}).
+Move to the @samp{Reply-To} header (@code{message-goto-reply-to}).
 @item C-c C-f C-f
 Move to the @samp{Mail-Followup-To} header field
 (@code{message-goto-followup-to}).
diff --git a/doc/misc/efaq.texi b/doc/misc/efaq.texi
index 96ca465..0649ed5 100644
--- a/doc/misc/efaq.texi
+++ b/doc/misc/efaq.texi
@@ -4463,11 +4463,11 @@ Saving a copy of outgoing mail
 @cindex Automatic filing of outgoing mail
 @cindex Mail, saving outgoing automatically
 
-You can either mail yourself a copy by including a @samp{BCC} header in the
+You can either mail yourself a copy by including a @samp{Bcc} header in the
 mail message, or store a copy of the message directly to a file by
-including an @samp{FCC} header.
+including an @samp{Fcc} header.
 
-If you use standard mail, you can automatically create a @samp{BCC} to
+If you use standard mail, you can automatically create a @samp{Bcc} to
 yourself by putting
 
 @lisp
@@ -4475,7 +4475,7 @@ Saving a copy of outgoing mail
 @end lisp
 
 @noindent
-in your @file{.emacs} file.  You can automatically include an @samp{FCC}
+in your @file{.emacs} file.  You can automatically include an @samp{Fcc}
 field by putting something like the following in your @file{.emacs}
 file:
 
@@ -4485,7 +4485,7 @@ Saving a copy of outgoing mail
 
 The output file will be in Unix mail format.
 
-If you use @code{mh-e}, add an @samp{FCC} or @samp{BCC} field to your
+If you use @code{mh-e}, add an @samp{Fcc} or @samp{Bcc} field to your
 components file.
 
 It does not work to put @samp{set record filename} in the @file{.mailrc}
@@ -4562,8 +4562,8 @@ Replying to the sender of a message
 
 @c isaacson@@seas.upenn.edu
 Ron Isaacson says: When you hit
-@kbd{r} to reply in Rmail, by default it CCs all of the original
-recipients (everyone on the original @samp{To} and @samp{CC}
+@kbd{r} to reply in Rmail, by default it Ccs all of the original
+recipients (everyone on the original @samp{To} and @samp{Cc}
 lists). With a prefix argument (i.e., typing @kbd{C-u} before @kbd{r}),
 it replies only to the sender.  However, going through the whole
 @kbd{C-u} business every time you want to reply is a pain.  This is the
diff --git a/doc/misc/emacs-mime.texi b/doc/misc/emacs-mime.texi
index 3925cce..c30403d 100644
--- a/doc/misc/emacs-mime.texi
+++ b/doc/misc/emacs-mime.texi
@@ -708,7 +708,7 @@ MML Definition
 
 @item recipients
 Who to encrypt/sign the part to.  This field is used to override any
-auto-detection based on the To/CC headers.
+auto-detection based on the To/Cc headers.
 
 @item sender
 Identity used to sign the part.  This field is used to override the
diff --git a/doc/misc/gnus-faq.texi b/doc/misc/gnus-faq.texi
index efef01f..2ae5a0a 100644
--- a/doc/misc/gnus-faq.texi
+++ b/doc/misc/gnus-faq.texi
@@ -1161,13 +1161,13 @@ FAQ 4-15
 @example
 (setq nnmail-split-methods
   '(("duplicates" "^Gnus-Warning:.*duplicate")
-    ("XEmacs-NT" "^\\(To:\\|CC:\\).*localpart@@xemacs.invalid.*")
-    ("Gnus-Tut" "^\\(To:\\|CC:\\).*localpart@@socha.invalid.*")
-    ("tcsh" "^\\(To:\\|CC:\\).*localpart@@mx.gw.invalid.*")
-    ("BAfH" "^\\(To:\\|CC:\\).*localpart@@.*uni-muenchen.invalid.*")
-    ("Hamster-src" "^\\(CC:\\|To:\\).*hamster-sourcen@@yahoogroups.\\(de\\|com\\).*")
+    ("XEmacs-NT" "^\\(To:\\|Cc:\\).*localpart@@xemacs.invalid.*")
+    ("Gnus-Tut" "^\\(To:\\|Cc:\\).*localpart@@socha.invalid.*")
+    ("tcsh" "^\\(To:\\|Cc:\\).*localpart@@mx.gw.invalid.*")
+    ("BAfH" "^\\(To:\\|Cc:\\).*localpart@@.*uni-muenchen.invalid.*")
+    ("Hamster-src" "^\\(Cc:\\|To:\\).*hamster-sourcen@@yahoogroups.\\(de\\|com\\).*")
     ("Tagesschau" "^From: tagesschau <localpart@@www.tagesschau.invalid>$")
-    ("Replies" "^\\(CC:\\|To:\\).*localpart@@Frank-Schmitt.invalid.*")
+    ("Replies" "^\\(Cc:\\|To:\\).*localpart@@Frank-Schmitt.invalid.*")
     ("EK" "^From:.*\\(localpart@@privateprovider.invalid\\|localpart@@workplace.invalid\\).*")
     ("Spam" "^Content-Type:.*\\(ks_c_5601-1987\\|EUC-KR\\|big5\\|iso-2022-jp\\).*")
     ("Spam" "^Subject:.*\\(This really work\\|XINGA\\|ADV:\\|XXX\\|adult\\|sex\\).*")
@@ -1177,10 +1177,10 @@ FAQ 4-15
     ("Spam" "^From:.*\\(verizon\.net\\|prontomail\.com\\|money\\|ConsumerDirect\\).*")
     ("Spam" "^Delivered-To: GMX delivery to spamtrap@@gmx.invalid$")
     ("Spam" "^Received: from link2buy.com")
-    ("Spam" "^CC: .*azzrael@@t-online.invalid")
+    ("Spam" "^Cc: .*azzrael@@t-online.invalid")
     ("Spam" "^X-Mailer-Version: 1.50 BETA")
-    ("Uni" "^\\(CC:\\|To:\\).*localpart@@uni-koblenz.invalid.*")
-    ("Inbox" "^\\(CC:\\|To:\\).*\\(my\ name\\|address@@one.invalid\\|address@@two.invalid\\)")
+    ("Uni" "^\\(Cc:\\|To:\\).*localpart@@uni-koblenz.invalid.*")
+    ("Inbox" "^\\(Cc:\\|To:\\).*\\(my\ name\\|address@@one.invalid\\|address@@two.invalid\\)")
     ("Spam" "")))
 @end example
 @noindent
diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 0fdb28f..6793ed2 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -5592,7 +5592,7 @@ Summary Mail Commands
 Mail a wide reply to the author of the current article
 (@code{gnus-summary-wide-reply}).  A @dfn{wide reply} is a reply that
 goes out to all people listed in the @code{To}, @code{From} (or
-@code{Reply-to}) and @code{Cc} headers.  If @code{Mail-Followup-To} is
+@code{Reply-To}) and @code{Cc} headers.  If @code{Mail-Followup-To} is
 present, that's used instead.
 
 @item S W
@@ -5616,7 +5616,7 @@ Summary Mail Commands
 Mail a very wide reply to the author of the current article
 (@code{gnus-summary-wide-reply}).  A @dfn{very wide reply} is a reply
 that goes out to all people listed in the @code{To}, @code{From} (or
-@code{Reply-to}) and @code{Cc} headers in all the process/prefixed
+@code{Reply-To}) and @code{Cc} headers in all the process/prefixed
 articles.  This command uses the process/prefix convention.
 
 @item S V
diff --git a/doc/misc/message.texi b/doc/misc/message.texi
index 671a521..3d342f5 100644
--- a/doc/misc/message.texi
+++ b/doc/misc/message.texi
@@ -174,7 +174,7 @@ Wide Reply
 The @code{message-wide-reply} pops up a message buffer that's a wide
 reply to the message in the current buffer.  A @dfn{wide reply} is a
 reply that goes out to all people listed in the @code{To}, @code{From}
-(or @code{Reply-to}) and @code{Cc} headers.
+(or @code{Reply-To}) and @code{Cc} headers.
 
 @vindex message-wide-reply-to-function
 Message uses the normal methods to determine where wide replies are to go,
@@ -2056,7 +2056,7 @@ News Headers
 @item quoting-style
 Check whether text follows last quoted portion.
 @item repeated-newsgroups
-Check whether the @code{Newsgroups} and @code{Followup-to} headers
+Check whether the @code{Newsgroups} and @code{Followup-To} headers
 contains repeated group names.
 @item reply-to
 Check whether the @code{Reply-To} header looks ok.
@@ -2069,7 +2069,7 @@ News Headers
 @item shoot
 Check whether the domain part of the @code{Message-ID} header looks ok.
 @item shorten-followup-to
-Check whether to add a @code{Followup-to} header to shorten the number
+Check whether to add a @code{Followup-To} header to shorten the number
 of groups to post to.
 @item signature
 Check the length of the signature.
@@ -2080,7 +2080,7 @@ News Headers
 @item subject-cmsg
 Check the subject for commands.
 @item valid-newsgroups
-Check whether the @code{Newsgroups} and @code{Followup-to} headers
+Check whether the @code{Newsgroups} and @code{Followup-To} headers
 are valid syntactically.
 @end table
 
diff --git a/doc/misc/mh-e.texi b/doc/misc/mh-e.texi
index 7ec9aec..8545525 100644
--- a/doc/misc/mh-e.texi
+++ b/doc/misc/mh-e.texi
@@ -847,9 +847,9 @@ Processing Mail Tour
 To:
 cc:
 Subject: Re: Test
-In-reply-to: <31054.1142621351@@stop.mail-abuse.org>
+In-Reply-To: <31054.1142621351@@stop.mail-abuse.org>
 References: <31054.1142621351@@stop.mail-abuse.org>
-Comments: In-reply-to Bill Wohler <wohler@@stop.mail-abuse.org>
+Comments: In-Reply-To Bill Wohler <wohler@@stop.mail-abuse.org>
    message dated "Fri, 17 Mar 2006 10:49:11 -0800."
 X-Mailer: MH-E 8.1; nmh 1.1; GNU Emacs 23.1
 --------
diff --git a/etc/NEWS.18 b/etc/NEWS.18
index 153c2f7..e2645b9 100644
--- a/etc/NEWS.18
+++ b/etc/NEWS.18
@@ -201,10 +201,10 @@ is carried over to the expansion that replaces it.
 has the syntax of an ordinary punctuation character.  As a result,
 \[...\] and such like are considered to balance each other.
 
-* Mail-mode automatic Reply-to field.
+* Mail-mode automatic Reply-To field.
 
 If the variable `mail-default-reply-to' is non-`nil', then each time
-you start to compose a message, a Reply-to field is inserted with
+you start to compose a message, a Reply-To field is inserted with
 its contents taken from the value of `mail-default-reply-to'.
 
 * Where is your .emacs file?
diff --git a/etc/NEWS.19 b/etc/NEWS.19
index 12432ea..efe0f0e 100644
--- a/etc/NEWS.19
+++ b/etc/NEWS.19
@@ -438,7 +438,7 @@ The other accent characters, not needed for the chosen language,
 remain normal.
 
 ** Posting articles and sending mail now has M-TAB completion on various
-header fields (Newsgroups, To, CC, ...).
+header fields (Newsgroups, To, Cc, ...).
 
 Completion in the Newsgroups header depends on the list of groups
 known to your news reader.  Completion in the Followup-To header
@@ -2087,7 +2087,7 @@ arguments are ARGS.
 for mail-default-reply-to.
 
 ** When you send a message in Emacs, if you specify an Rmail file with
-the FCC: header field, Emacs converts the message to Rmail format
+the Fcc: header field, Emacs converts the message to Rmail format
 before writing it.  Thus, the file never contains anything but Rmail
 format messages.
 
diff --git a/etc/NEWS.20 b/etc/NEWS.20
index 31e640f..398148b 100644
--- a/etc/NEWS.20
+++ b/etc/NEWS.20
@@ -986,7 +986,7 @@ be prompted for confirmation
 
 **** can generate a MESSAGE-ID: line and a DATE: line; the date can be
 the time the message was written or the time it is being sent; this
-can make FCC copies more closely resemble copies that recipients get
+can make Fcc copies more closely resemble copies that recipients get
 
 **** you can specify an arbitrary function for actually transmitting
 the message; included in feedmail are interfaces for /bin/[r]mail,
diff --git a/etc/refcards/cs-survival.tex b/etc/refcards/cs-survival.tex
index 908ca96..574e5d2 100644
--- a/etc/refcards/cs-survival.tex
+++ b/etc/refcards/cs-survival.tex
@@ -289,7 +289,7 @@ \section{Čtení a posílání pošty}
 
 \key{C-x m} nová zpráva
 \key{C-c C-c} pošli zprávu a přepni do jiného bufferu
-\key{C-c C-f C-c} přesuň se na hlavičku `CC' a pokud neexistuje, tak ji
+\key{C-c C-f C-c} přesuň se na hlavičku `Cc' a pokud neexistuje, tak ji
 vytvoř
 
 \section{Různé}
diff --git a/etc/refcards/fr-survival.tex b/etc/refcards/fr-survival.tex
index f74e2ad..a622642 100644
--- a/etc/refcards/fr-survival.tex
+++ b/etc/refcards/fr-survival.tex
@@ -287,7 +287,7 @@ \section{Lecture et envoi de courrier}
 
 \key{C-x m} d\'ebute la composition d'un message
 \key{C-c C-c} envoie le message et bascule dans un autre tampon
-\key{C-c C-f C-c} va \`a l'ent\^ete `CC', en cr\'ee un s'il n'existe pas
+\key{C-c C-f C-c} va \`a l'ent\^ete `Cc', en cr\'ee un s'il n'existe pas
 
 \section{Divers}
 
diff --git a/etc/refcards/sk-survival.tex b/etc/refcards/sk-survival.tex
index c4dab28..b063708 100644
--- a/etc/refcards/sk-survival.tex
+++ b/etc/refcards/sk-survival.tex
@@ -292,7 +292,7 @@ \section{Čítanie a posielanie pošty}
 
 \key{C-x m} nová správa
 \key{C-c C-c} pošli správu a prepni sa do iného bufferu
-\key{C-c C-f C-c} presuň sa na hlavičku `CC', a ak neexistuje, tak ju
+\key{C-c C-f C-c} presuň sa na hlavičku `Cc', a ak neexistuje, tak ju
 vytvor
 
 \section{Rôzne}
diff --git a/etc/refcards/survival.tex b/etc/refcards/survival.tex
index 5dee445..63fdde1 100644
--- a/etc/refcards/survival.tex
+++ b/etc/refcards/survival.tex
@@ -278,7 +278,7 @@ \section{Reading and Sending Mail}
 
 \key{C-x m} begin composing a message
 \key{C-c C-c} send the message and switch to another buffer
-\key{C-c C-f C-c} move to the `CC' header field, creating one
+\key{C-c C-f C-c} move to the `Cc' header field, creating one
   if there is none
 
 \section{Miscellaneous}
diff --git a/lisp/ChangeLog.2 b/lisp/ChangeLog.2
index 1b0ed42..a5a654a 100644
--- a/lisp/ChangeLog.2
+++ b/lisp/ChangeLog.2
@@ -1229,7 +1229,7 @@
 1987-05-13  Richard M. Stallman  (rms@prep)
 
 	* sendmail.el (mail-setup): New parameter mail-default-reply-to:
-	if non-nil, insert it as a Reply-to field.
+	if non-nil, insert it as a Reply-To field.
 
 	* dired.el (dired-unflag): Doc fix.
 
@@ -3924,7 +3924,7 @@
 	New key bindings for setting insert motion direction:
 	C-c <, C-c >, C-c ^ and C-c . instead of M- chars.
 
-	* rmail.el (rmail-reply): When putting From into In-reply-to,
+	* rmail.el (rmail-reply): When putting From into In-Reply-To,
 	stop at any newline.
 
 	* mail-utils.el (mail-strip-quoted-names):
diff --git a/lisp/ChangeLog.4 b/lisp/ChangeLog.4
index 8bdb6ba..0374e1b 100644
--- a/lisp/ChangeLog.4
+++ b/lisp/ChangeLog.4
@@ -3739,7 +3739,7 @@
 
 1994-01-10  Michael D. Ernst  (mernst@monozygote)
 
-	* mailabbrev.el (mail-abbrev-mode-regexp): Add Reply-to.
+	* mailabbrev.el (mail-abbrev-mode-regexp): Add Reply-To.
 
 1994-01-09  Roland McGrath  (roland@churchy.gnu.ai.mit.edu)
 
diff --git a/lisp/ChangeLog.5 b/lisp/ChangeLog.5
index 566e9b7..3a68421 100644
--- a/lisp/ChangeLog.5
+++ b/lisp/ChangeLog.5
@@ -991,7 +991,7 @@
 1995-05-19  Kevin Rodgers  <kevinr@ihs.com>  (tiny change)
 
 	* mailalias.el (expand-mail-aliases): Expand aliases in
-	From and Reply-to headers as well, plus the Resent- variants.
+	From and Reply-To headers as well, plus the Resent- variants.
 
 	* sendmail.el (mail-mode): Clarify doc string.
 	(mail-text): Ditto.
diff --git a/lisp/ChangeLog.7 b/lisp/ChangeLog.7
index f534b6e..27cbe10 100644
--- a/lisp/ChangeLog.7
+++ b/lisp/ChangeLog.7
@@ -21076,7 +21076,7 @@
 1996-12-17  Jonathan I. Kamens  <jik@cam.ov.com>
 
 	* rnewspost.el (news-mail-reply, news-reply): Include the message
-	ID in the In-reply-to line.
+	ID in the In-Reply-To line.
 
 1996-12-16  Erik Naggum  <erik@naggum.no>
 
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index f6120dc..055f02f 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -198,9 +198,9 @@ gnus-boring-article-headers
   `newsgroups'  Newsgroup identical to Gnus group.
   `to-address'  To identical to To-address.
   `to-list'     To identical to To-list.
-  `cc-list'     CC identical to To-list.
-  `followup-to' Followup-to identical to Newsgroups.
-  `reply-to'    Reply-to identical to From.
+  `cc-list'     Cc identical to To-list.
+  `followup-to' Followup-To identical to Newsgroups.
+  `reply-to'    Reply-To identical to From.
   `date'        Date less than four days old.
   `long-to'     To and/or Cc longer than 1024 characters.
   `many-to'     Multiple To and/or Cc."
@@ -208,9 +208,9 @@ gnus-boring-article-headers
 	      (const :tag "Newsgroups identical to Gnus group." newsgroups)
 	      (const :tag "To identical to To-address." to-address)
 	      (const :tag "To identical to To-list." to-list)
-	      (const :tag "CC identical to To-list." cc-list)
-	      (const :tag "Followup-to identical to Newsgroups." followup-to)
-	      (const :tag "Reply-to identical to From." reply-to)
+	      (const :tag "Cc identical to To-list." cc-list)
+	      (const :tag "Followup-To identical to Newsgroups." followup-to)
+	      (const :tag "Reply-To identical to From." reply-to)
 	      (const :tag "Date less than four days old." date)
 	      (const :tag "To and/or Cc longer than 1024 characters." long-to)
 	      (const :tag "Multiple To and/or Cc headers." many-to))
@@ -1947,7 +1947,7 @@ article-hide-boring-headers
 		(when (and cc to-list
 			   (ignore-errors
 			     (gnus-string-equal
-			      ;; only one address in CC
+			      ;; only one address in Cc
 			      (nth 1 (mail-extract-address-components cc))
 			      to-list)))
 		  (gnus-article-hide-header "cc"))))
diff --git a/lisp/gnus/gnus-msg.el b/lisp/gnus/gnus-msg.el
index 6505f90..660bdf7 100644
--- a/lisp/gnus/gnus-msg.el
+++ b/lisp/gnus/gnus-msg.el
@@ -1038,7 +1038,7 @@ gnus-post-news
 	  (gnus-inews-yank-articles yank))))))
 
 (defun gnus-msg-treat-broken-reply-to (&optional force)
-  "Remove the Reply-to header if broken-reply-to."
+  "Remove the Reply-To header if broken-reply-to."
   (when (or force
 	    (gnus-group-find-parameter
 	     gnus-newsgroup-name 'broken-reply-to))
@@ -1483,7 +1483,7 @@ gnus-summary-mail-crosspost-complaint
 		   (not (member group (message-tokenize-header
 				       followup-to ", ")))))
 	  (if followup-to
-	      (gnus-message 1 "Followup-to restricted")
+	      (gnus-message 1 "Followup-To restricted")
 	    (gnus-message 1 "Not a crossposted article"))
 	(set-buffer gnus-summary-buffer)
 	(gnus-summary-reply-with-original 1)
diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index 867c3d2..7cc4d61 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -1252,13 +1252,13 @@ message-default-mail-headers
   ;; Ease the transition from mail-mode to message-mode.  See bugs#4431, 5555.
   (concat (if (and (boundp 'mail-default-reply-to)
 		   (stringp mail-default-reply-to))
-	      (format "Reply-to: %s\n" mail-default-reply-to))
+	      (format "Reply-To: %s\n" mail-default-reply-to))
 	  (if (and (boundp 'mail-self-blind)
 		   mail-self-blind)
-	      (format "BCC: %s\n" user-mail-address))
+	      (format "Bcc: %s\n" user-mail-address))
 	  (if (and (boundp 'mail-archive-file-name)
 		   (stringp mail-archive-file-name))
-	      (format "FCC: %s\n" mail-archive-file-name))
+	      (format "Fcc: %s\n" mail-archive-file-name))
 	  mail-default-headers)
   "A string of header lines to be inserted in outgoing mails."
   :version "23.2"
@@ -2597,7 +2597,7 @@ message-info
 		       'message)))))
 
 (defun message-all-recipients ()
-  "Return a list of all recipients in the message, looking at TO, CC and BCC.
+  "Return a list of all recipients in the message, looking at TO, Cc and Bcc.
 
 Each recipient is in the format of `mail-extract-address-components'."
   (mapcan (lambda (header)
@@ -3563,7 +3563,7 @@ message-insert-disposition-notification-to
       (message-remove-header "Disposition-Notification-To"))
     (message-goto-eoh)
     (insert (format "Disposition-Notification-To: %s\n"
-		    (or (message-field-value "Reply-to")
+		    (or (message-field-value "Reply-To")
 			(message-field-value "From")
 			(message-make-from))))))
 
@@ -5439,7 +5439,7 @@ message-do-fcc
 	       (concat "^" (regexp-quote mail-header-separator) "$")
 	       nil t)
 	  (replace-match "" t t ))
-	;; Process FCC operations.
+	;; Process Fcc operations.
 	(while list
 	  (setq file (pop list))
 	  (if (string-match "^[ \t]*|[ \t]*\\(.*\\)[ \t]*$" file)
diff --git a/lisp/mail/feedmail.el b/lisp/mail/feedmail.el
index e0bd459..6093aec 100644
--- a/lisp/mail/feedmail.el
+++ b/lisp/mail/feedmail.el
@@ -1396,7 +1396,7 @@ feedmail-last-chance-hook
 When this hook runs, the current buffer is already the appropriate
 buffer.  It has already had all the header prepping from the standard
 package.  The next step after running the hook will be to save the
-message via FCC: processing. The hook might be interested in these:
+message via Fcc: processing. The hook might be interested in these:
 \(1) `feedmail-prepped-text-buffer' contains the header and body of the
 message, ready to go; (2) `feedmail-address-list' contains a list
 of simplified recipients of addresses which are to be given to the
@@ -1607,7 +1607,7 @@ feedmail-buffer-to-sendmail
   "Function which actually calls sendmail as a subprocess.
 Feeds the buffer to it.  Probably has some flaws for Resent-* and other
 complicated cases.  Takes addresses from message headers and
-might disappoint you with BCC: handling.  In case of odd results, consult
+might disappoint you with Bcc: handling.  In case of odd results, consult
 local gurus."
   (require 'sendmail)
   (feedmail-say-debug ">in-> feedmail-buffer-to-sendmail %s" addr-listoid)
diff --git a/lisp/mail/mail-utils.el b/lisp/mail/mail-utils.el
index fc9f8dd..463cec0 100644
--- a/lisp/mail/mail-utils.el
+++ b/lisp/mail/mail-utils.el
@@ -41,7 +41,7 @@ mail-dont-reply-to-names
 If this is nil, it is set the first time you compose a reply, to
 a value which excludes your own email address.
 
-Matching addresses are excluded from the CC field in replies, and
+Matching addresses are excluded from the Cc field in replies, and
 also the To field, unless this would leave an empty To field."
   :type '(choice regexp (const :tag "Your Name" nil))
   :group 'mail)
diff --git a/lisp/mail/mailabbrev.el b/lisp/mail/mailabbrev.el
index 99c0671..ba1688f 100644
--- a/lisp/mail/mailabbrev.el
+++ b/lisp/mail/mailabbrev.el
@@ -25,7 +25,7 @@
 
 ;;; Commentary:
 
-;; This file ensures that, when the point is in a To:, CC:, BCC:, or From:
+;; This file ensures that, when the point is in a To:, Cc:, Bcc:, or From:
 ;; field, word-abbrevs are defined for each of your mail aliases.  These
 ;; aliases will be defined from your .mailrc file (or the file specified by
 ;; `mail-personal-alias-file') if it exists.  Your mail aliases will
@@ -414,7 +414,7 @@ mail-abbrev-expand-hook
 ;;; Syntax tables and abbrev-expansion
 
 (defcustom mail-abbrev-mode-regexp
-  "^\\(Resent-\\)?\\(To\\|From\\|CC\\|BCC\\|Reply-to\\):"
+  "^\\(Resent-\\)?\\(To\\|From\\|Cc\\|Bcc\\|Reply-To\\):"
   "Regexp matching mail headers in which mail abbrevs should be expanded.
 This string will be handed to `looking-at' with point at the beginning
 of the current line; if it matches, abbrev mode will be turned on, otherwise
@@ -477,7 +477,7 @@ mail-abbrev-expand-wrapper
 	      ;; Necessary for `message-read-from-minibuffer' to work.
 	      (window-minibuffer-p))
 
-          ;; We are in a To: (or CC:, or whatever) header or a minibuffer,
+          ;; We are in a To: (or Cc:, or whatever) header or a minibuffer,
           ;; and should use word-abbrevs to expand mail aliases.
           (let ((local-abbrev-table mail-abbrevs))
 
diff --git a/lisp/mail/mailalias.el b/lisp/mail/mailalias.el
index 424ae67..17b4cdf 100644
--- a/lisp/mail/mailalias.el
+++ b/lisp/mail/mailalias.el
@@ -50,14 +50,14 @@ mail-directory-names
 When t this still needs to be initialized.")
 
 (defvar mail-address-field-regexp
-  "^\\(Resent-\\)?\\(To\\|From\\|CC\\|BCC\\|Reply-to\\):")
+  "^\\(Resent-\\)?\\(To\\|From\\|Cc\\|Bcc\\|Reply-To\\):")
 
 (defvar pattern)
 
 (defcustom mail-complete-alist
   ;; Don't refer to mail-address-field-regexp here;
   ;; that confuses some things such as cus-dep.el.
-  '(("^\\(Resent-\\)?\\(To\\|From\\|CC\\|BCC\\|Reply-to\\):"
+  '(("^\\(Resent-\\)?\\(To\\|From\\|Cc\\|Bcc\\|Reply-To\\):"
      . (mail-get-names pattern))
     ("Newsgroups:" . (if (boundp 'gnus-active-hashtb)
                          gnus-active-hashtb
@@ -169,7 +169,7 @@ mail-local-names
 (defun expand-mail-aliases (beg end &optional exclude)
   "Expand all mail aliases in suitable header fields found between BEG and END.
 If interactive, expand in header fields.
-Suitable header fields are `To', `From', `CC' and `BCC', `Reply-to', and
+Suitable header fields are `To', `From', `Cc' and `Bcc', `Reply-To', and
 their `Resent-' variants.
 
 Optional second arg EXCLUDE may be a regular expression defining text to be
diff --git a/lisp/mail/rfc2047.el b/lisp/mail/rfc2047.el
index c0cd4ee..282fd38 100644
--- a/lisp/mail/rfc2047.el
+++ b/lisp/mail/rfc2047.el
@@ -293,7 +293,7 @@ rfc2047-encode-message-header
 		(if mail-parse-charset
 		    (encode-coding-region (point) (point-max)
 					  mail-parse-charset)))
-	       ;; We get this when CC'ing messages to newsgroups with
+	       ;; We get this when Cc'ing messages to newsgroups with
 	       ;; 8-bit names.  The group name mail copy just got
 	       ;; unconditionally encoded.  Previously, it would ask
 	       ;; whether to encode, which was quite confusing for the
diff --git a/lisp/mail/rmail-spam-filter.el b/lisp/mail/rmail-spam-filter.el
index ab0417b..99c1a1c 100644
--- a/lisp/mail/rmail-spam-filter.el
+++ b/lisp/mail/rmail-spam-filter.el
@@ -251,7 +251,7 @@ rmail-spam-filter
         (setq message-subject (mail-fetch-field "Subject"))
         (setq message-content-type (mail-fetch-field "Content-Type"))
         (setq message-spam-status (mail-fetch-field "X-Spam-Status")))
-      ;; Check for blind CC condition.  Set vars such that while
+      ;; Check for blind cc condition.  Set vars such that while
       ;; loop will be bypassed and spam condition will trigger.
       (and rsf-no-blind-cc
            (null message-recipients)
diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 0f4bb1f..12a58b2 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -851,7 +851,7 @@ rmail-font-lock-keywords
 	       (beginning-of-line) (end-of-line)
 	       (1 font-lock-comment-delimiter-face nil t)
 	       (5 font-lock-comment-face nil t)))
-	    '("^\\(X-[a-z0-9-]+\\|In-reply-to\\|Date\\):.*\\(\n[ \t]+.*\\)*$"
+	    '("^\\(X-[a-z0-9-]+\\|In-Reply-To\\|Date\\):.*\\(\n[ \t]+.*\\)*$"
 	      . 'rmail-header-name))))
   "Additional expressions to highlight in Rmail mode.")
 
@@ -3789,7 +3789,7 @@ rmail-continue
 
 (defun rmail-reply (just-sender)
   "Reply to the current message.
-Normally include CC: to all other recipients of original message;
+Normally include Cc: to all other recipients of original message;
 prefix argument means ignore them.  While composing the reply,
 use \\[mail-yank-original] to yank the original message into it."
   (interactive "P")
@@ -3823,7 +3823,7 @@ rmail-reply
        (unless just-sender
 	 (if (mail-fetch-field "mail-followup-to" nil t)
 	     ;; If this header field is present, use it instead of the
-	     ;; To and CC fields.
+	     ;; To and Cc fields.
 	     (setq to (mail-fetch-field "mail-followup-to" nil t))
 	   (setq cc (or (mail-fetch-field "cc" nil t) "")
 		 to (or (mail-fetch-field "to" nil t) ""))))))
@@ -4275,7 +4275,7 @@ rmail-retry-failure
 	      (if mail-self-blind
 		  (if resending
 		      (insert "Resent-Bcc: " (user-login-name) "\n")
-		    (insert "BCC: " (user-login-name) "\n"))))
+		    (insert "Bcc: " (user-login-name) "\n"))))
 	    (goto-char (point-min))
 	    (mail-position-on-field (if resending "Resent-To" "To") t))))))
 \f
diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index 692f67b..3dd486a 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -1626,7 +1626,7 @@ rmail-summary-continue
 
 (defun rmail-summary-reply (just-sender)
   "Reply to the current message.
-Normally include CC: to all other recipients of original message;
+Normally include Cc: to all other recipients of original message;
 prefix argument means ignore them.  While composing the reply,
 use \\[mail-yank-original] to yank the original message into it."
   (interactive "P")
diff --git a/lisp/mail/sendmail.el b/lisp/mail/sendmail.el
index f1c6d39..aebc50f 100644
--- a/lisp/mail/sendmail.el
+++ b/lisp/mail/sendmail.el
@@ -107,9 +107,9 @@ mail-envelope-from
 
 ;;;###autoload
 (defcustom mail-self-blind nil
-  "Non-nil means insert BCC to self in messages to be sent.
+  "Non-nil means insert Bcc to self in messages to be sent.
 This is done when the message is initialized,
-so you can remove or alter the BCC field to override the default."
+so you can remove or alter the Bcc field to override the default."
   :type 'boolean
   :group 'sendmail)
 
@@ -188,7 +188,7 @@ mail-archive-file-name
 
 ;;;###autoload
 (defcustom mail-default-reply-to nil
-  "Address to insert as default Reply-to field of outgoing messages.
+  "Address to insert as default Reply-To field of outgoing messages.
 If nil, it will be initialized from the REPLYTO environment variable
 when you first send mail."
   :type '(choice (const nil) string)
@@ -473,7 +473,7 @@ mail-font-lock-keywords
 	   (cite-prefix "[:alpha:]")
 	   (cite-suffix (concat cite-prefix "0-9_.@-`'\"")))
       (list '("^\\(To\\|Newsgroups\\):" . font-lock-function-name-face)
-	    '("^\\(B?CC\\|Reply-to\\|Mail-\\(reply\\|followup\\)-to\\):" . font-lock-keyword-face)
+	    '("^\\(B?Cc\\|Reply-To\\|Mail-\\(Reply\\|Followup\\)-To\\):" . font-lock-keyword-face)
 	    '("^\\(Subject:\\)[ \t]*\\(.+\\)?"
 	      (1 font-lock-comment-face)
 ;;	      (2 font-lock-type-face nil t)
@@ -493,7 +493,7 @@ mail-font-lock-keywords
 	       (beginning-of-line) (end-of-line)
 	       (1 font-lock-comment-delimiter-face nil t)
 	       (5 font-lock-comment-face nil t)))
-	    '("^\\(X-[A-Za-z0-9-]+\\|In-reply-to\\):.*\\(\n[ \t]+.*\\)*$"
+	    '("^\\(X-[A-Za-z0-9-]+\\|In-Reply-To\\):.*\\(\n[ \t]+.*\\)*$"
 	      . font-lock-string-face))))
   "Additional expressions to highlight in Mail mode.")
 
@@ -642,7 +642,7 @@ mail-setup
       (newline))
     (if cc
 	(let ((fill-prefix "\t")
-	      (address-start (progn (insert "CC: ") (point))))
+	      (address-start (progn (insert "Cc: ") (point))))
 	  (insert cc "\n")
 	  (fill-region-as-paragraph address-start (point-max))
 	  (goto-char (point-max))
@@ -652,7 +652,7 @@ mail-setup
 	(let ((fill-prefix "\t")
 	      (fill-column 78)
 	      (address-start (point)))
-	  (insert "In-reply-to: " in-reply-to "\n")
+	  (insert "In-Reply-To: " in-reply-to "\n")
 	  (fill-region-as-paragraph address-start (point-max))
 	  (goto-char (point-max))
 	  (unless (bolp)
@@ -661,11 +661,11 @@ mail-setup
     (if mail-default-headers
 	(insert mail-default-headers))
     (if mail-default-reply-to
-	(insert "Reply-to: " mail-default-reply-to "\n"))
+	(insert "Reply-To: " mail-default-reply-to "\n"))
     (if mail-self-blind
-	(insert "BCC: " user-mail-address "\n"))
+	(insert "Bcc: " user-mail-address "\n"))
     (if mail-archive-file-name
-	(insert "FCC: " mail-archive-file-name "\n"))
+	(insert "Fcc: " mail-archive-file-name "\n"))
     (put-text-property (point)
 		       (progn
 			 (insert mail-header-separator "\n")
@@ -701,8 +701,8 @@ mail-mode
 
 Here are commands that move to a header field (and create it if there isn't):
 	 \\[mail-to]  move to To:	\\[mail-subject]  move to Subj:
-	 \\[mail-bcc]  move to BCC:	\\[mail-cc]  move to CC:
-	 \\[mail-fcc]  move to FCC:	\\[mail-reply-to] move to Reply-To:
+	 \\[mail-bcc]  move to Bcc:	\\[mail-cc]  move to Cc:
+	 \\[mail-fcc]  move to Fcc:	\\[mail-reply-to] move to Reply-To:
          \\[mail-mail-reply-to]  move to Mail-Reply-To:
          \\[mail-mail-followup-to] move to Mail-Followup-To:
 \\[mail-text]  move to message text.
@@ -913,7 +913,7 @@ mail-send
                         (regexp-opt mail-mailing-lists t)
                         "\\(?:[[:space:];,]\\|\\'\\)"))))
         (mail-combine-fields "To")
-        (mail-combine-fields "CC")
+        (mail-combine-fields "Cc")
 	;; If there are mailing lists defined
 	(when ml
 	  (save-excursion
@@ -1229,7 +1229,7 @@ sendmail-send-it
 	  ;; the message specially.
 	  (let ((case-fold-search t))
 	    (goto-char (point-min))
-	    (while (re-search-forward "^Resent-\\(to\\|cc\\|bcc\\):" delimline t)
+	    (while (re-search-forward "^Resent-\\(To\\|Cc\\|Bcc\\):" delimline t)
 	      ;; Put a list of such addresses in resend-to-addresses.
 	      (setq resend-to-addresses
 		    (save-restriction
@@ -1241,7 +1241,7 @@ sendmail-send-it
 					  (point)))
 		      (append (mail-parse-comma-list)
 			      resend-to-addresses)))
-	      ;; Delete Resent-BCC ourselves
+	      ;; Delete Resent-Bcc ourselves
 	      (if (save-excursion (beginning-of-line)
 				  (looking-at "resent-bcc"))
 		  (delete-region (line-beginning-position)
@@ -1304,9 +1304,9 @@ sendmail-send-it
 	    (goto-char (1+ delimline))
 	    (if (eval mail-mailer-swallows-blank-line)
 		(newline))
-	    ;; Find and handle any FCC fields.
+	    ;; Find and handle any Fcc fields.
 	    (goto-char (point-min))
-	    (if (re-search-forward "^FCC:" delimline t)
+	    (if (re-search-forward "^Fcc:" delimline t)
 		(progn
 		  (setq fcc-was-found t)
 		  (mail-do-fcc delimline)))
@@ -1380,8 +1380,8 @@ sendmail-send-it
 (autoload 'rmail-output-to-rmail-buffer "rmailout")
 
 (defun mail-do-fcc (header-end)
-  "Find and act on any FCC: headers in the current message before HEADER-END.
-If a buffer is visiting the FCC file, append to it before
+  "Find and act on any Fcc: headers in the current message before HEADER-END.
+If a buffer is visiting the Fcc file, append to it before
 offering to save it, if it was modified initially.  If this is an
 Rmail buffer, update Rmail as needed.  If there is no buffer,
 just append to the file, in Babyl format if necessary."
@@ -1393,7 +1393,7 @@ mail-do-fcc
     (save-excursion
       (goto-char (point-min))
       (let ((case-fold-search t))
-	(while (re-search-forward "^FCC:[ \t]*" header-end t)
+	(while (re-search-forward "^Fcc:[ \t]*" header-end t)
 	  (push (buffer-substring (point)
 				  (progn
 				    (end-of-line)
@@ -1472,7 +1472,7 @@ mail-do-fcc
 		  ;; If the file is a Babyl file, convert the message to
 		  ;; Babyl format.  Even though Rmail no longer uses
 		  ;; Babyl, this code can remain for the time being, on
-		  ;; the off-chance one FCCs to a Babyl file that has
+		  ;; the off-chance one Fccs to a Babyl file that has
 		  ;; not yet been converted to mbox.
 		  (let ((coding-system-for-write
 			 (or rmail-file-coding-system 'emacs-mule)))
@@ -1493,7 +1493,7 @@ mail-do-fcc
 		   (set-visited-file-modtime)))))))))
 
 (defun mail-sent-via ()
-  "Make a Sent-via header line from each To or CC header line."
+  "Make a Sent-via header line from each To or Cc header line."
   (declare (obsolete "nobody can remember what it is for." "24.1"))
   (interactive)
   (save-excursion
@@ -1528,7 +1528,7 @@ mail-subject
   (mail-position-on-field "Subject"))
 
 (defun mail-cc ()
-  "Move point to end of CC field, creating it if necessary."
+  "Move point to end of Cc field, creating it if necessary."
   (interactive)
   (expand-abbrev)
   (or (mail-position-on-field "cc" t)
@@ -1536,20 +1536,20 @@ mail-cc
 	     (insert "\nCC: "))))
 
 (defun mail-bcc ()
-  "Move point to end of BCC field, creating it if necessary."
+  "Move point to end of Bcc field, creating it if necessary."
   (interactive)
   (expand-abbrev)
   (or (mail-position-on-field "bcc" t)
       (progn (mail-position-on-field "to")
-	     (insert "\nBCC: "))))
+	     (insert "\nBcc: "))))
 
 (defun mail-fcc (folder)
-  "Add a new FCC field, with file name completion."
+  "Add a new Fcc field, with file name completion."
   (interactive "FFolder carbon copy: ")
   (expand-abbrev)
-  (or (mail-position-on-field "fcc" t)	;Put new field after exiting FCC.
+  (or (mail-position-on-field "fcc" t)	;Put new field after exiting Fcc.
       (mail-position-on-field "to"))
-  (insert "\nFCC: " folder))
+  (insert "\nFcc: " folder))
 
 (defun mail-reply-to ()
   "Move point to end of Reply-To field, creating it if necessary."
@@ -1852,13 +1852,13 @@ mail
 to move to message header fields:
 \\{mail-mode-map}
 
-If `mail-self-blind' is non-nil, a BCC to yourself is inserted
+If `mail-self-blind' is non-nil, a Bcc to yourself is inserted
 when the message is initialized.
 
 If `mail-default-reply-to' is non-nil, it should be an address (a string);
-a Reply-to: field with that address is inserted.
+a Reply-To: field with that address is inserted.
 
-If `mail-archive-file-name' is non-nil, an FCC field with that file name
+If `mail-archive-file-name' is non-nil, an Fcc field with that file name
 is inserted.
 
 The normal hook `mail-setup-hook' is run after the message is
diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index 403a5c3..8bc3cc7 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -321,11 +321,11 @@ smtpmail-send-it
 	    (goto-char (1+ delimline))
 	    (if (eval mail-mailer-swallows-blank-line)
 		(newline))
-	    ;; Find and handle any FCC fields.
+	    ;; Find and handle any Fcc fields.
 	    (goto-char (point-min))
-	    (if (re-search-forward "^FCC:" delimline t)
+	    (if (re-search-forward "^Fcc:" delimline t)
 		;; Force `mail-do-fcc' to use the encoding of the mail
-		;; buffer to encode outgoing messages on FCC files.
+		;; buffer to encode outgoing messages on Fcc files.
 		(let ((coding-system-for-write
 		       ;; mbox files must have Unix EOLs.
 		       (coding-system-change-eol-conversion
@@ -992,9 +992,9 @@ smtpmail-deduce-address-list
 	  ;; RESENT-* fields should stop processing of regular fields.
 	  (save-excursion
 	    (setq addr-regexp
-		  (if (re-search-forward "^Resent-\\(to\\|cc\\|bcc\\):"
+		  (if (re-search-forward "^Resent-\\(To\\|Cc\\|Bcc\\):"
 					 header-end t)
-		      "^Resent-\\(to\\|cc\\|bcc\\):"
+		      "^Resent-\\(To\\|Cc\\|Bcc\\):"
 		    "^\\(To:\\|Cc:\\|Bcc:\\)")))
 
 	  (while (re-search-forward addr-regexp header-end t)
@@ -1027,14 +1027,14 @@ smtpmail-deduce-address-list
 	    (setq smtpmail-recipient-address-list recipient-address-list))))))
 
 (defun smtpmail-do-bcc (header-end)
-  "Delete [Resent-]BCC: and their continuation lines from the header area.
-There may be multiple BCC: lines, and each may have arbitrarily
+  "Delete [Resent-]Bcc: and their continuation lines from the header area.
+There may be multiple Bcc: lines, and each may have arbitrarily
 many continuation lines."
   (let ((case-fold-search t))
     (save-excursion
       (goto-char (point-min))
-      ;; iterate over all BCC: lines
-      (while (re-search-forward "^\\(RESENT-\\)?BCC:" header-end t)
+      ;; iterate over all Bcc: lines
+      (while (re-search-forward "^\\(RESENT-\\)?Bcc:" header-end t)
 	(delete-region (match-beginning 0)
 		       (progn (forward-line 1) (point)))
 	;; get rid of any continuation lines
diff --git a/lisp/mail/uce.el b/lisp/mail/uce.el
index b948acf..dfe5c9c 100644
--- a/lisp/mail/uce.el
+++ b/lisp/mail/uce.el
@@ -338,7 +338,7 @@ uce-reply-to-uce
 	(if mail-default-headers
 	    (insert mail-default-headers))
 	(if mail-default-reply-to
-	    (insert "Reply-to: " mail-default-reply-to "\n"))
+	    (insert "Reply-To: " mail-default-reply-to "\n"))
 	(insert mail-header-separator "\n")
 	;; Insert all our text.  Then go back to the place where we started.
 	(if to (setq to (point)))
diff --git a/lisp/mh-e/mh-comp.el b/lisp/mh-e/mh-comp.el
index 9415293..1a77daf 100644
--- a/lisp/mh-e/mh-comp.el
+++ b/lisp/mh-e/mh-comp.el
@@ -324,7 +324,7 @@ mh-send-letter
       ;; message in your +outbox, and best of all doesn't break threading for
       ;; the recipient if you reply to a message in your +outbox.
       (setq mh-send-args (concat "-msgid " mh-send-args))
-      ;; The default BCC encapsulation will make a MIME message unreadable.
+      ;; The default Bcc encapsulation will make a MIME message unreadable.
       ;; With nmh use the -mime arg to prevent this.
       (if (and (mh-variant-p 'nmh)
                (mh-goto-header-field "Bcc:")
diff --git a/lisp/mh-e/mh-show.el b/lisp/mh-e/mh-show.el
index 90e2411..dae8de0 100644
--- a/lisp/mh-e/mh-show.el
+++ b/lisp/mh-e/mh-show.el
@@ -774,7 +774,7 @@ mh-show-font-lock-keywords
     ("^\\(Apparently-To:\\|Newsgroups:\\)\\(.*\\)"
      (1 'default)
      (2 'mh-show-cc))
-    ("^\\(In-reply-to\\|Date\\):\\(.*\\)$"
+    ("^\\(In-Reply-To\\|Date\\):\\(.*\\)$"
      (1 'default)
      (2 'mh-show-date))
     (mh-letter-header-font-lock
diff --git a/lisp/obsolete/mailpost.el b/lisp/obsolete/mailpost.el
index eebaa34..2f74faf 100644
--- a/lisp/obsolete/mailpost.el
+++ b/lisp/obsolete/mailpost.el
@@ -54,10 +54,10 @@ post-mail-send-it
 	  (while (and (re-search-forward "\n\n\n*" delimline t)
 		      (< (point) delimline))
 	    (replace-match "\n"))
-	  ;; Find and handle any FCC fields.
+	  ;; Find and handle any Fcc fields.
 	  (let ((case-fold-search t))
 	    (goto-char (point-min))
-	    (if (re-search-forward "^FCC:" delimline t)
+	    (if (re-search-forward "^Fcc:" delimline t)
 		(mail-do-fcc delimline))
 	    ;; If there is a From and no Sender, put it a Sender.
 	    (goto-char (point-min))
diff --git a/test/lisp/gnus/message-tests.el b/test/lisp/gnus/message-tests.el
index 27b8c10..7fa0fe9 100644
--- a/test/lisp/gnus/message-tests.el
+++ b/test/lisp/gnus/message-tests.el
@@ -102,8 +102,8 @@
 (ert-deftest message-all-recipients ()
   (ert-with-test-buffer (:name "message")
     (insert "To: Person 1 <p1@p1.org>, Person 2 <p2@p2.org>\n")
-    (insert "CC: Person 3 <p3@p3.org>, Person 4 <p4@p4.org>\n")
-    (insert "BCC: Person 5 <p5@p5.org>, Person 6 <p6@p6.org>\n")
+    (insert "Cc: Person 3 <p3@p3.org>, Person 4 <p4@p4.org>\n")
+    (insert "Bcc: Person 5 <p5@p5.org>, Person 6 <p6@p6.org>\n")
     (should (equal (message-all-recipients)
                    '(("Person 1" "p1@p1.org")
                      ("Person 2" "p2@p2.org")
-- 
2.7.4

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Eli Zaretskii]

> Cc: emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sun, 20 May 2018 11:08:20 -0700
> 
> Since "CC" also stands for "CC Mode", "Creative Commons" and suchlike, it's 
> useful for Emacs to stick with the RFC 5322 capitalization to distinguish email 
> Cc from the other CC usages. I installed the attached into master to try to be 
> more consistent about this.

Sorry, such blatant disregard for my opinions is unacceptable, as is
extreme disrespect to the work I do on the manuals.  So I reverted
part of your changeset that "fixed" the manuals.

Please don't do that again.  If nothing more, it's simply unfair.

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Stefan Monnier]

>>> -The @samp{To}, @samp{Cc}, and @samp{Bcc} fields can appear any number
>>> +The @samp{To}, @samp{CC}, and @samp{BCC} fields can appear any number
>> FWIW, I can't remember seeing "CC:" or "BCC:" in an email message
>> whereas I've seen "Cc:" and "Bcc:" many many times.  So my reaction to
>> the above line would be "Huh?  Why didn't they write `TO` to
>> be consistent?"
> Also, RFC 2822 always uses the capitalized form (the only exception is
> Message-ID).

To clarify: while I do have a personal preference for capitalizing
instead of using allcaps, the only thing I care about is that we either
use "allcaps for all" (i.e. "TO" and "CC") or "capitalize for all" ("To"
and "Cc").


        Stefan

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Paul Eggert]

Eli Zaretskii wrote:
> such blatant disregard for my opinions is unacceptable, as is
> extreme disrespect to the work I do on the manuals.

I didn't notice who had made the changes to the manuals, and there was no 
personal disrespect to you. My goal was merely consistency with the RFCs and 
with common practice, and I had no idea that this would annoy you. If you prefer 
all-caps then of course you're the maintainer. Feel free to revert my entire 
change, as none of this is worth any hard feelings.

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Eli Zaretskii]

> Cc: monnier@IRO.UMontreal.CA, emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sun, 20 May 2018 17:24:50 -0700
> 
> My goal was merely consistency with the RFCs and with common
> practice

The RFC tells how the email software should work, but it has no
bearing on how we write our manuals.  I have no objections to the
non-manual changes you made, and didn't revert them.

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > FWIW, I can't remember seeing "CC:" or "BCC:" in an email message
  > > whereas I've seen "Cc:" and "Bcc:" many many times.  So my reaction to
  > > the above line would be "Huh?  Why didn't they write `TO` to
  > > be consistent?"

  > Also, RFC 2822 always uses the capitalized form (the only exception is
  > Message-ID).

Let's not write "TO".  It would be inconvenient for readers
and offers no advantage.

-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)
Skype: No way! See https://stallman.org/skype.html.

Re: [Emacs-diffs] emacs-26 0d8bae5: Fix capitalization of mail headers

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> CC: monnier@IRO.UMontreal.CA, eliz@gnu.org, emacs-devel@gnu.org
> Date: Mon, 21 May 2018 00:15:01 -0400
> 
> Let's not write "TO".

No, of course not.