bug#66190: 30.0.50; ns-use-proxy-icon has no effect on macOS 12.6.9

[Stefan Kangas]

In emacs -Q, the `ns-use-proxy-icon' option (introduced in Emacs 27)
doesn't appear to have any effect on macOS 12.6.9.  See the attached
screenshot, and compare it to the one here:

https://emacs.stackexchange.com/questions/33680/how-to-remove-the-icon-in-the-titlebar

Changing the value to nil also seems to have no effect.

While we're at it, the documentation of this could be clearer; neither
the manual nor the docstring explain what a "proxy icon" even is.  I had
to search online, and find the above link, to understand what it is
supposed to do.

In addition, can this variable be set in a running Emacs?  The above
Stackoverflow link suggests that you might need to restart Emacs, but
AFAICT there is nothing about that in our documentation.

Am I missing something about how this is supposed to work?


In GNU Emacs 30.0.50 (build 1, x86_64-apple-darwin21.6.0, NS
 appkit-2113.60 Version 12.6.9 (Build 21G726)) of 2023-09-25 built on
 MY-MacBook-Pro
Repository revision: 22fe8955c21dbcc5c7c422a9917f77bf73794cc4
Repository branch: HEAD
Windowing system distributor 'Apple', version 10.3.2113
System Description:  macOS 12.6.9

Configured using:
 'configure --with-native-compilation'

Configured features:
ACL GIF GMP GNUTLS JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP NOTIFY
KQUEUE NS PDUMPER PNG SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER WEBP XIM ZLIB

Important settings:
  value of $LC_COLLATE: C
  value of $LC_CTYPE: sv_SE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  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
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-regexp-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr compile comint ansi-osc ansi-color ring emacsbug
message mailcap yank-media puny dired dired-loaddefs rfc822 mml mml-sec
password-cache epa derived epg rfc6068 epg-config gnus-util
text-property-search mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils time-date cl-print byte-opt comp comp-cstr
warnings icons subr-x rx cl-seq cl-macs gv cl-extra bytecomp
byte-compile thingatpt help-fns radix-tree help-mode cl-loaddefs cl-lib
rmc iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win touch-screen 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 nadvice seq simple cl-generic
indonesian philippine 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 abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads kqueue cocoa ns lcms2
multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 98657 9013) (symbols 48 8006 0) (strings 32 24246 1887)
 (string-bytes 1 712069) (vectors 16 17617)
 (vector-slots 8 357076 11706) (floats 8 32 44) (intervals 56 294 0)
 (buffers 992 13))

ns-use-proxy-icon.png
Description: PNG image