Hi
the solution is in this post...
VistaLover
Hi. As I understood maintainers of upstream projects which Basilisk 52 and 55 is derived from are going to drop .XPI extension format compatibility eventually? Can @roytam1 discard those changes to his builds from upstream projects and maintain XPI compatibility in his builds of Basilisk 52 and 55? If so, is he planning to?
Unfortunately, the solution proposed, i.e. Moon Tester Tool, moon-tester-tool-2.0.1.xpi didn't install either in Basilisk 52 and 55, gave compatibility error. Can something in install.rdf inside that xpi be edited to allow its installation?