Hm. I tried to verify that the changes I described were still in place, and it turns out that "Allow Firefox to send technical and interaction data to Mozilla" and "Allow Firefox to install and run studies" were still checked, though I DID uncheck them. The "xpinstall.signatures.required" setting is still set to true.
Well, now everything is working AFTER i refreshed firefox and hosed all my settings practically- what a pain getting them back the way i like them-
I was able to uncheck “Allow Firefox to install and run studies”- and closed FF reopened, and it’s still unchecked and my “xpinstall.signatures.required” is still set to false- not sure why yours got rechecked?