@Maholmire @BrodieOnLinux Yep, that's definitely a crossposter then. They're using a bridge. You can set up a bridge on your own account without needing an admin to do anything, since you'll most likely only have to log in and that's it.
But if you're asking about the names of said bridges, I have no idea. I don't use them myself, and personally dislike them so I never really looked into what people use to crosspost their content