This is probably an unpopular opinion, but I would love to see ActivityPub implementations not tied to a GPL/AGPL license. After poking at WriteFreely, the only thing stopping me from PRing a half-dozen improvements is the weird license choice.
AGPL/GPL is terrible if you want to write stuff that you can reuse for other projects (commercial or personal). Viral licenses tie the hands of the original authors as much as those of contributors. Folks tend to figure this out only when it is really difficult to fix (ie. getting (C) reassignment or CLAs in place for all past contributors).
You can work around it by putting code into freely licensed subpackages instead, but it forces weird design decisions. I get that some folks are concerned about being SaaSed, but the AGPL choice still has a cost.
Anywho, MIT/BSD licenses are your friend now, and a friend to your future self who needs to reuse that code for something else in a decade.