pgp.mit.edu don’t seem to have it either.
I did a few searches and everyone seems to be using apks signed by it. Or the ones signed by it have the same “shasum -a 256” (Do others get the same hashsum of F-Droid's apk?)
So guessing that you are safe. Would have been nice if someone jumped on here to put your concern to rest but I’m having the same disinterest in my thread. Maybe it’s the summer fun that everyone is having in the northern hemisphere or something haha.