The app appears to be "Forum, a Facebook app":

https://apps.apple.com/us/app/forum-a-facebook-app/id6758308...

Posts:

https://www.engadget.com/2179165/meta-forum-groups-app/

https://www.threads.com/@mattnavarra/post/DYnoSuSCjXq

https://firethering.com/meta-forum-reddit-like-app-facebook-...