We officially revived the developer website!
https://www.gimp.org/news/2022/10/16/gimp-developer-website-rewrite/
It should help for new contributor inboarding and plug-in developers. It's still work-in-progress and quite incomplete but published in a release early, release often logic.
Thanks to @patdavid (who made our main website and pixls.us), Jehan (@zemarmot project and GIMP maintainer), Robin Swift (new contributor who helped us a lot here) and Lukas Oberhuber (macOS package maintainer)!