Marcus Lundblad created an issue:
As Maps is currently using libchamplain and this is depending on Clutter, we'll need to move from away from it to be able to migrate to GTK 4. For that reason, I forked libchamplain a while back into a new project libshumate: https://gitlab.gnome.org/mlundblad/libshumate to be able to accomplish a similar API, but target native GTK 4 APIs. Currently there has been some more interest from others to contribute to it: mlundblad/libshumate#2. I think the project would qualify to use one of the shared namespaces as it's intended eventually be part of GNOME (used as a dependency of Maps, and replacing libchamplain, which is currently maintained in GNOME. I think to start out with I (mlundblad) could continue maintenance of this project.
Thanks :)