In fact I have modified the bat to add a "lib2" folder where I can easier manage extension jars.
set CP=%MAIN%/BaseX.jar;%MAIN%/lib/*;%MAIN%/lib2/*
Good point. For the Windows executable, I thought about adding a 'custom' sub-directory in the lib folder. The jars in the lib directory could be deleted with each update, but the custom folder would be preserved.
But is the original problem a bug? That is after installing the jar via REPO install t:new("aaa") fails although it works when added to lib/
Be sure I’ll check this out later this week.