I always wondered what that icon was for until I just hovered over it and it's apparently somethingwith lemmy.world. Can we have something like that too?

Also, what causes this icon to appear? On the middle post neither the poster nor the community is on lemmy.world. Do they just put the symbol everywhere they feel like?

EDIT:

Turns out, that icon is not from lemmy.world specifically, but for the general Fediverse. It highlights posts which are not from your instance (so not from blahaj zone).