Thanks @Indranil Roy, there is a merge request pending so we may not need a patch?
As a followup, there is also PHPStan issue that we found but it'll require either rewriting a function or just renaming it in the sub-theme when one is generated.
PHP Fatal error: Cannot redeclare _is_page_link_visible() (previously declared in /Users/myuser/Work/client/web/themes/contrib/governor/governor.theme:55) in /Users/myuser/Work/client/web/themes/custom/client/client.theme on line 70
The workaround, for now, is to rename the global function inside client.theme - but this could be fixed permanently perhaps if a service was provided by the base theme. If needed, I can file another issue for that.
saltednut → created an issue.
Not seeing documentation around MV or much usage? Option 2 sounds really doable and doesn't require an experimental module. Converting things over to services has been a goal since we moved to this architecture so I'd lean toward supporting that.