bug#69483: 29.2; "\fC" macro in ox-man.el

[Xiyue Deng]

"mu4e"[1] (a popular Emacs mail client) uses Org to generate its
manpages.  However, the generated output contains macros that are not
understood by groff.  After some debugging, Jeremy traced this back to
the macro "\fC" used in ox-man.el[2].  Git history shows that this may
have been there since the beginning.  We tried to find a documentation
for the "\fC" macro but has not been able to find one.  Jeremy suggests
that "C" may be an old alias for Courier, and if that's the case it
should be changed to "\f[CR]".  Would be great if Org people can
confirm.

[1] https://github.com/djcb/mu
[2] E.g. 
https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/org/ox-man.el#n362
    (Credit to Jeremy Sowden <jeremy@azazel.net>)


In GNU Emacs 29.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.38,
 cairo version 1.16.0) of 2024-01-20, modified by Debian built on
 debian-hx90
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
System Description: Debian GNU/Linux 12 (bookworm)

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 
--enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.2/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 
--enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.2/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --with-cairo --with-x=yes
 --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -ffile-prefix-map=/build/emacs-0t7K2r/emacs-29.2+1=. -fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3
THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XDBE XIM XINPUT2
XPM GTK3 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  pyvenv-mode: t
  TeX-PDF-mode: t
  global-git-commit-mode: t
  magit-auto-revert-mode: t
  shell-dirtrack-mode: t
  flyspell-mode: t
  rcirc-track-minor-mode: t
  windmove-mode: t
  server-mode: t
  subword-mode: t
  bug-reference-prog-mode: t
  whitespace-mode: t
  yas-minor-mode: t
  global-company-mode: t
  company-mode: t
  global-treesit-auto-mode: t
  activities-tabs-mode: t
  activities-mode: t
  icomplete-mode: t
  fido-mode: t
  override-global-mode: t
  global-display-line-numbers-mode: t
  display-line-numbers-mode: t
  global-auto-revert-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  tab-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/debian-el-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/debian-el-autoloads
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/apt-sources hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/apt-sources
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/debian-bug hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/debian-bug
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/apt-utils hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/apt-utils
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/debian-el-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/debian-el-pkg
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/gnus-BTS hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/gnus-BTS
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/deb-view hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/deb-view
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/debian-el hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/debian-el
/usr/share/emacs/site-lisp/elpa/debian-el-37.11/preseed hides 
/usr/share/emacs/site-lisp/elpa-src/debian-el-37.11/preseed
/usr/share/emacs/site-lisp/elpa/devscripts-40/devscripts hides 
/usr/share/emacs/site-lisp/elpa-src/devscripts-40/devscripts
/usr/share/emacs/site-lisp/elpa/devscripts-40/devscripts-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/devscripts-40/devscripts-autoloads
/usr/share/emacs/site-lisp/elpa/devscripts-40/pbuilder-mode hides 
/usr/share/emacs/site-lisp/elpa-src/devscripts-40/pbuilder-mode
/usr/share/emacs/site-lisp/elpa/devscripts-40/devscripts-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/devscripts-40/devscripts-pkg
/usr/share/emacs/site-lisp/elpa/devscripts-40/pbuilder-log-view-mode hides 
/usr/share/emacs/site-lisp/elpa-src/devscripts-40/pbuilder-log-view-mode
/usr/share/emacs/site-lisp/elpa/dockerfile-mode-1.7/dockerfile-mode hides 
/usr/share/emacs/site-lisp/elpa-src/dockerfile-mode-1.7/dockerfile-mode
/usr/share/emacs/site-lisp/elpa/dockerfile-mode-1.7/dockerfile-mode-autoloads 
hides 
/usr/share/emacs/site-lisp/elpa-src/dockerfile-mode-1.7/dockerfile-mode-autoloads
/usr/share/emacs/site-lisp/elpa/dockerfile-mode-1.7/dockerfile-mode-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/dockerfile-mode-1.7/dockerfile-mode-pkg
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/debian-bts-control hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/debian-bts-control
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/debian-changelog-mode hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/debian-changelog-mode
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/dpkg-dev-el-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/dpkg-dev-el-autoloads
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/dpkg-dev-el-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/dpkg-dev-el-pkg
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/dpkg-dev-el hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/dpkg-dev-el
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/debian-control-mode hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/debian-control-mode
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/debian-copyright hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/debian-copyright
/usr/share/emacs/site-lisp/elpa/dpkg-dev-el-37.10/readme-debian hides 
/usr/share/emacs/site-lisp/elpa-src/dpkg-dev-el-37.10/readme-debian
/usr/share/emacs/site-lisp/elpa/lintian-0.1/lintian-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/lintian-0.1/lintian-pkg
/usr/share/emacs/site-lisp/elpa/lintian-0.1/lintian-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/lintian-0.1/lintian-autoloads
/usr/share/emacs/site-lisp/elpa/lintian-0.1/lintian hides 
/usr/share/emacs/site-lisp/elpa-src/lintian-0.1/lintian
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode-pkg
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode-autoloads
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode hides 
/usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode
/usr/share/emacs/site-lisp/elpa/py-isort-2016.1/py-isort hides 
/usr/share/emacs/site-lisp/elpa-src/py-isort-2016.1/py-isort
/usr/share/emacs/site-lisp/elpa/py-isort-2016.1/py-isort-autoloads hides 
/usr/share/emacs/site-lisp/elpa-src/py-isort-2016.1/py-isort-autoloads
/usr/share/emacs/site-lisp/elpa/py-isort-2016.1/py-isort-pkg hides 
/usr/share/emacs/site-lisp/elpa-src/py-isort-2016.1/py-isort-pkg
/home/xiyueden/.config/emacs/elpa/transient-0.5.3/transient hides 
/usr/share/emacs/29.2/lisp/transient

Features:
(shadow emacsbug pyvenv eshell esh-cmd esh-ext esh-opt esh-proc esh-io
esh-arg esh-module esh-groups esh-util python perl-mode
debian-control-mode ffap dockerfile-ts-mode yaml-ts-mode sh-script
executable nroff-mode magit-patch magit-subtree magit-gitignore
magit-ediff ediff ediff-merg ediff-mult ediff-wind ediff-diff ediff-help
ediff-init ediff-util scheme c++-ts-mode c-ts-mode c-ts-common
meson-mode smie find-dired grep make-mode tex-info texinfo
texinfo-loaddefs tex texmathp debian-copyright boxquote rect view
deb-view tar-mode arc-mode archive-mode git-rebase gitignore-mode
conf-mode readme-debian debian-bug debian-changelog-mode goto-addr
magit-extras magit-bookmark magit-submodule magit-obsolete magit-blame
magit-stash magit-reflog magit-bisect magit-push magit-pull magit-fetch
magit-clone magit-remote magit-commit magit-sequence magit-notes
magit-worktree magit-tag magit-merge magit-branch magit-reset
magit-files magit-refs magit-status magit magit-repos magit-apply
magit-wip magit-log which-func magit-diff git-commit log-edit add-log
magit-core magit-autorevert magit-margin magit-transient magit-process
magit-mode transient magit-git magit-section dired-aux org-element
org-persist org-id org-refile avl-tree oc-basic ol-eww eww xdg mm-url
ol-rmail ol-mhe ol-irc ol-info ol-gnus nnselect ol-docview doc-view
image-mode exif ol-bibtex bibtex ol-bbdb ol-w3m ol-doi org-link-doi org
ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-src ob-comint
org-pcomplete org-list org-footnote org-faces org-entities noutline
outline ob-emacs-lisp ob-core ob-eval org-cycle org-table ol org-fold
org-fold-core org-keys oc org-loaddefs cal-menu calendar cal-loaddefs
org-version org-compat org-macs srecode/srt-mode semantic/analyze
semantic/sort semantic/scope semantic/analyze/fcn semantic/db
semantic/format ezimage srecode/template srecode/srt-wy semantic/wisent
semantic/wisent/wisent semantic/ctxt srecode/ctxt semantic/tag-ls
semantic/find srecode/compile srecode/dictionary srecode/fields
srecode/table srecode eieio-base semantic/util-modes semantic/util
semantic semantic/tag semantic/lex semantic/fw mode-local cedet eglot
external-completion array jsonrpc ert ewoc debug backtrace imenu
cl-print help-fns radix-tree mailalias misearch multi-isearch
magit-utils crm dash with-editor compat vterm tramp tramp-loaddefs
trampver tramp-integration files-x tramp-compat format-spec face-remap
term shell pcomplete ehelp find-func vterm-module smerge-mode diff
shr-color jka-compr flow-fill matlab matlab-scan matlab-syntax
matlab-compat pulse color qp url-http url-gw url-auth mule-util sort
gnus-cite url-queue url-cache mm-archive mail-extr textsec uni-scripts
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gnus-bcklg gnus-ml gnus-topic cursor-sensor utf-7 nnfolder gnus-demon
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score-mode nnvirtual nntp gnus-cache gnus-msg gnus-art mm-uu mml2015
mm-view mml-smime smime dig gnus-sum shr pixel-fill kinsoku url-file svg
dom nndraft nnmh gnus-group gnus-undo smtpmail gnus-start gnus-dbus dbus
xml gnus-cloud nnimap nnmail mail-source utf7 nnoo gnus-spec gnus-int
gnus-range message sendmail yank-media dired dired-loaddefs rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mailabbrev gmm-utils mailheader gnus-win gnus nnheader
gnus-util mail-utils range mm-util mail-prsvr flyspell ispell gnutls
network-stream puny nsm epa-file epa derived epg rfc6068 epg-config
rcirc parse-time iso8601 time-date windmove term/xterm xterm comp
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vc-bzr vc-src vc-sccs vc-svn vc-cvs vc-rcs log-view pcvs-util vc
vc-dispatcher bug-reference disp-table whitespace yasnippet cus-edit
cus-start wid-edit company-oddmuse company-keywords company-etags etags
fileloop generator xref company-gtags company-dabbrev-code
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pyvenv-autoloads rust-mode-autoloads scala-mode-autoloads
transient-autoloads treesit-auto-autoloads vterm-autoloads
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electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
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romanian slovak czech european ethiopic indian cyrillic chinese
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hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
native-compile emacs)

Memory information:
((conses 16 5651518 443398)
 (symbols 48 48454 64)
 (strings 32 242258 64673)
 (string-bytes 1 8647819)
 (vectors 16 170061)
 (vector-slots 8 4122334 278922)
 (floats 8 1162 9185)
 (intervals 56 315902 18543)
 (buffers 984 164))