The “proper” way to link magazines from lemmy would be lemmy.world/c/cars@kbin.social - this is supposed to fetch a clone of the kbin magazine but display it in the lemmy.world UI. Using a “c” is correct here, but something still doesn’t work properly for this particular instance.

If you write it as kbin.social/m/cars, then you’re directed to the original magazine with the kbin UI.

The same works the other way around too: lemmy.world/c/support will open the support-community on lemmy.world in its original state, and kbin.social/m/support@lemmy.world will open the LW-support community clone as a magazine on kbin, with the kbin UI. (you might need to copypaste that last link instead of clicking it, as LW seems to “fix” the link by automatically converting it into lemmy.world/c/support@lemmy.world )

Long story short, the c/w thing is not the issue as it works for other communities and magazines just fine. Still, somehow the content in this case doesn’t federate properly … maybe someone who can take a look at the actual code might have an idea why? I mean, sooner or later this needs to be fixed. The magazines listed in the original comment are surely not the only ones that are affected, and any magazine that looks dead and abandoned from this side of the Fediverse, is a magazine that won’t gain any subscribers, posts and comments FROM this side of the Fediverse, defeating the idea behind Federation. It slows down growth.