The 'disable-user-extensions' GSettings key is the last extensions-related
setting that isn't exposed over D-Bus, and therefore requires consumers
to access the GSettings directly.
Expose the setting as UserExtensionsEnabled readwrite property in the
org.gnome.Shell.Extensions interface to allow consumers to manage
extensions purely via D-Bus.
The 'disable-user-extensions' setting is the last extension-related
bit from the org.gnome.shell GSettings schema that is not exposed
via D-Bus.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1074
3a39fb5ab8