See attached screenshot from `emacs -Q' followed by M-x speedbar.

Some of the file names are followed by a codepoint 35 character (`#')
that is displayed as a blue matrix of tiny 0s and 1s.  Other file names
have no such character after them.  (Not shown: read-only files have
instead a yellow padlock icon following the file name.)

`C-u C-x =' on that character gives this info:

             position: 21143 of 44023 (48%), column: 18
            character: # (displayed as #) (codepoint 35, #o43, #x23)
    preferred charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x23
               script: latin
               syntax: . 	which means: punctuation
             category: .:Base, a:ASCII, l:Latin, r:Roman
             to input: type "C-x 8 RET HEX-CODEPOINT" or "C-x 8 RET NAME"
          buffer code: #x23
            file code: #x23 (encoded by coding system iso-latin-1-dos)
              display: by this font (glyph code)
    uniscribe:-outline-Courier New-normal-normal-normal-mono-17-*-*-*-c-*-iso8859-1 (#x06)

Character code properties: customize what to show
  name: NUMBER SIGN
  general-category: Po (Punctuation, Other)
  decomposition: (35) ('#')

There are text properties here:
  display              [Show]
  rear-nonsticky       [Show]

However, where the text copied above shows "# (displayed as #)", what
I actually see in buffer *Help* is "# (displayed as [])", where `[]'
is that blue binary matrix char display.

Seems like a bug of some kind.  `C-h m' says that character `#' after
a file name indicates that the file has been compiled:

"Files with a `#' or `!' character after them are source files that
 have an object file associated with them.  The `!' indicates that the
 files is out of date.  You can control what source/object associations
 exist through the variable `speedbar-obj-alist'."

So it seems that the bug is that the `#' char is displayed wrong (in
both speedbar and `C-u C-x =' output).

(A second comment about the speedbar display, in passing: Why does it
use a different face for mouseover from the default face for this
elsewhere, `highlight'?  If a user has gone to the trouble of
customizing face `highlight', why would that not be used here also?)


In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-08-23 on ODIEONE
Bzr revision: 113986 rgm@gnu.org-20130823185841-zoy6h1qk433ibrlf
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 'CFLAGS=-O0 -g3' LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'