I’ve seen this mentioned a few times already: people wondering why certain communities don’t show up in their instance. You need to first search for that community via the magnifying glass icon and type in “!communityname@instance.domain”
Notice the exclamation mark at the beginning. Might take a few seconds. This will teach your instance about the remote community.
So I managed to get the extension to an usable state.
It adds that little kbin icon to the beginning of the url or mention, if you click that icon you will go to the kbin link of that community. It works for all websites so if you are browsing on a lemmy site it should work there too.
I am currently working on testing it and publishing it to the chrome and firefox stores.