No, you moved the goalposts. The original person you replied to said "Same with a Firefox extension." not a "nightly or developer build of Firefox extension".

No, you moved the goalposts. The original person you replied to said "Same with a Firefox extension." not a "nightly or developer build of Firefox extension". If you can't get an extension on a regular build of Firefox, you might as well not be able to do it because for most users installing nightly or dev is a big problem.