Hi @lynorian. In another post, @wxl suggested some good links for SDDM theme development (Github, IRC channel…). Maybe these would be good things to include in the Manual, in the section on modifying the log-in/lock screen. To generalize, maybe adding more development info/links throughout the manual would help direct new users of Lubuntu to resources so they(we) don’t have to come to the Discourse and ask about them here.
I certainly think the development info/links would be helpful.