1 pointYeah, that searches all filetypes. What sometimes happens is that different files of the same type actually have different UTIs assigned to them, so they aren’t found when looking by filetype.
1 pointWhenever you have this question, the answer is, “When Mozilla adds AppleScript support to Firefox.” The reason so few workflows support Firefox is because Mozilla makes it extremely difficult to do so. You need to go tell them to fix Firefox at the link below if you ever want that to change. https://bugzilla.mozilla.org/show_bug.cgi?id=125419