I brought up this issue on emacs-devel but the discussion did not
proceed beyond
https://lists.gnu.org/archive/html/emacs-devel/2025-02/msg01054.html

for decades find-func.el had used `find-function-setup-keys' to set up
global bindings to functions in find-func.el.  Since these are global
bindings these did not require a minor mode.

The minor-mode was introduced in c3e989ca9d7, "New minor mode
find-function-mode replaces find-function-setup-keys" which introduced
a keymap via new features.

This was objected to on the emacs-devel list by Eshel in
+message-id:<m1ed4wfaym.fsf@dazzs-mbp.home> (sorry lists.gnu.org
namazu apparently websearch by mid does not work or provide 
a link to the html mailing list) on "Fri, 04 Oct 2024 11:56:17 +0200"

and the commit 1094c3f914 "find-function-mode: Define keys at a low
precedence level" was introduced to restore "backward compatibility".


However this is an incorrect use of define-minor-mode, The use of
define-minor-mode is to explicitly use a keymap to shadow global
bindings and using it to modify global bindings is a basic category
error a thinko and should not be promoted in the code base.

as the functions in find-func.el are always available for binding, a
minor mode does not make sense, if only to mutate global bindings.

global bindings set by the user when the mode is in effect are undone
when the mode is removed. Emacs should not be doing this.

I believe The original function find-function-setup-keys' introduced
by rms explicitly avoided using a minor mode precisely for these reasons. Introducing a minor mode is a conceptual regression.

If a local keymap is not desired, the minor mode should be removed and
the original function undeprecated.

The attached patch however restores the local keymap but sets up global
bindings via the original find-function-setup-keys.