Figured it out mostly. Seems like some instances have a “main” community you can navigate to. Others just have their name, like this instance’s lemmy.world’s local feed viewed from another instance world be:

https://sh.itjust.works/c/lemmyworld@lemmy.world

Same for looking at lemmy.ml’s local feed from our instance:

https://lemmy.world/c/lemmy@lemmy.ml

Or, to use shit again, here’s what their main page feed looks like as viewed from our instance:

https://lemmy.world/c/main@sh.itjust.works