Szos hit it!
We're mostly in maintenance mode, however new features contributed by the community push stumpwm in exciting ways. I try to make releases twice a year, but its closer to once a year around Thanksgiving when I have an uninterrupted day to myself.
If you can find an issue (those tagged 'good first issue' are judged to be good for newer contributors, though I don't keep them as up to date as I should) take a shot, when you've got it solved open a PR and we'll review and merge it.
The wiki, and the info manual are places where its super easy to contribute, especially if you have unique configs or have discovered little known features that deserve more attention.
Welcome to our cozy part of the lisp community!
David