@noodlejetski
@kbin.socialdoesn't look that way. if you go to the last page, you'll see small communities from other services like Lemmy, Friendica, and Guppe Groups.
they're both parts of the Fediverse and are both link aggregators. similar to how, as a Lemmy user, you can subscribe to a community from a Lemmy instance ("server") different that you're on, you can subscribe to kbin communities the same way. I'm posting this comment from my kbin account.
you'd have to create another account with the same name over there. there's not much point though, if you see a community over there that you'd want to subscribe, you can do that from your current account.
it's on the IzzyOnDroid repo, not the official one, hence the 404. when you use "share link" option in the official F-droid client, it will generate an F-droid repo URL based on the app's package name, regardless of whether the app is in that repo or not. here's the proper link:
https://apt.izzysoft.de/fdroid/index/apk/com.hjiangsu.thunder
also, you really don't need to put "title" in the post body.