what is the meaning of posts with "via programming.dev" ?

I'm still getting the hang of Lemmy and federated services.

I'm browsing the programming.dev instandce in the Liftoff app and I can choose to view:

1. my subscribed communities on the server (currently none)
2. Local communities on the server
3. All (?)

I know All is not "all communities on Lemmy" but what perplexes me is I can see posts from another community that is hosted on a different server and it appears because it is "via programming.dev".

At first I thought it was because a user registered on " programming.dev " posted on another instance but I opened my eyes and saw the user's origin is no way related.

Any ideas?

EDIT:

After reading all the comments I’m pretty sure “via programming.dev” should read in the context of the post as !community@instance is known via programming.dev instance. I guess it makes it explicit which “all” I am browsing if I pick up browsing where I left off and forget I am not in the “all local”.

At this point I have only seen this on the Liftoff App for Lemmy but still trying other. Must be in the metadata and Liftoff decided to display it.