It's unused and was removed in commit a0467bf875, which broke extensions that rely on it in their preference widget. As the removal only happened post-3.36.0, add it back until we branch. https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2476
GNOME Shell
GNOME Shell provides core user interface functions for the GNOME 3 desktop, like switching to windows and launching applications. GNOME Shell takes advantage of the capabilities of modern graphics hardware and introduces innovative user interface concepts to provide a visually attractive and easy to use experience.
For more information about GNOME Shell, including instructions on how to build GNOME Shell from source and how to get involved with the project, see the project wiki.
Bugs should be reported to the GNOME bug tracking system.
Contributing
To contribute, open merge requests at https://gitlab.gnome.org/GNOME/gnome-shell.
Commit messages should follow the GNOME commit message guidelines. We require an URL to either an issue or a merge request in each commit.
License
GNOME Shell is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for details.