I finally got around to releasing a very rough prototype of Pushl to pypi. It only sends out WebSub notifications for now (does anyone even use those?), but I’ll work on actually implementing WebMention soon.
Also, recently someone pointed out to me fed.brid.gy which makes it easy to turn a static site into an ActivityPub source. At some point I’ll experiment with setting up Publ for this; it looks like it’s just a matter of adding a couple of additional route rules to Publ, so that will probably go into an advanced configuration guide if I ever get around to making such a thing. (Or it could actually be added to Publ directly but there isn’t much of a reason for that, IMO.)