LemmyBB, a traditional forum with ActivityPub
Interesting, I didn't know anyone was doing something like this. It's phpBB forum software, modified to be a front end for a Lemmy instance.
Announcement:First release of LemmyBB, a federated bulletin board written in Rust
"...This is an alternative frontend for Lemmy, based on the design of phpBB. It turns Lemmy from a link aggregator with upvotes and image previews into a traditional forum, or bulletin board. ... By combining these projects, we get the benefits of both: a stable and performant backend which supports Activitypub federation, has an extensive API with mod tools and much more. Together with a classical frontend that is focused on text-based discussion, with no distraction of voting or overt number of image posts. ..."