On a remote machine: dan@solstice:/tmp$ touch a b c dan@solstice:/tmp$ tar cf test.tar a b c dan@solstice:/tmp$ bzip2 -z test.tar dan@solstice:/tmp$ file test.tar.bz2 test.tar.bz2: bzip2 compressed data, block size = 900k If you visit that remote file and save it, the result will have the .bz2 extension but won't actually be compressed: dan@solstice:/tmp$ file test.tar.bz2 test.tar.bz2: POSIX tar archive (GNU) This doesn't happen with compressed remote files which aren't tar archives. In GNU Emacs 28.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.31, cairo version 1.16.0) of 2022-04-12 built on october.example.org Windowing system distributor 'The X.Org Foundation', version 11.0.12014000 System Description: Slackware 15.0 x86_64 Configured features: ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM GTK3 ZLIB Important settings: value of $LC_COLLATE: C value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: Fundamental Minor modes in effect: shell-dirtrack-mode: t hexl-follow-ascii: t tooltip-mode: t global-eldoc-mode: t electric-indent-mode: t mouse-wheel-mode: t tab-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Load-path shadows: ~/.emacs.d/lisp/android-mode hides /home/blakestone/.emacs.d/elpa/android-mode-20190903.811/android-mode ~/.emacs.d/lisp/connection hides /home/blakestone/.emacs.d/elpa/connection-20191111.446/connection ~/.emacs.d/lisp/link hides /home/blakestone/.emacs.d/elpa/link-20191111.446/link /home/blakestone/.emacs.d/elpa/transient-20220425.1314/transient hides /usr/local/share/emacs/28.1/lisp/transient /home/blakestone/.emacs.d/elpa/dictionary-20201001.1727/dictionary hides /usr/local/share/emacs/28.1/lisp/net/dictionary ~/.emacs.d/lisp/greek hides /usr/local/share/emacs/28.1/lisp/language/greek ~/.emacs.d/lisp/longlines hides /usr/local/share/emacs/28.1/lisp/obsolete/longlines Features: (shadow sort mail-extr ffap emacsbug message rmc puny rfc822 mml mml-sec epa epg rfc6068 epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils vc-hg vc-git diff-mode easy-mmode vc-bzr vc-dispatcher tar-mode arc-mode archive-mode jka-compr pcmpl-unix pcmpl-gnu with-editor compat dired-aux dired dired-loaddefs tramp-cache tramp-sh executable misearch multi-isearch edmacro kmacro cua-base cus-load acme-search quack thingatpt compile text-property-search cmuscheme scheme advice tramp tramp-loaddefs trampver tramp-integration files-x tramp-compat shell pcomplete comint ring parse-time iso8601 time-date ls-lisp format-spec ansi-color c-xref rx session vanc-init bindat vanc-mode hexl ecf-mode derived cl-extra help-mode dcm-general server cl info package browse-url url url-proxy url-privacy url-expand url-methods url-history url-cookie url-domsuf url-util mailcap url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs password-cache json subr-x map url-vars seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib iso-transl tooltip eldoc paren electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese composite emoji-zwj charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button loaddefs faces cus-face macroexp files window text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote threads dbusbind inotify lcms2 dynamic-setting system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs) Memory information: ((conses 16 166897 25031) (symbols 48 15286 4) (strings 32 52764 4059) (string-bytes 1 1727857) (vectors 16 31379) (vector-slots 8 983720 94988) (floats 8 84 70) (intervals 56 9204 1194) (buffers 992 22))