Seldom have I found any firefox app so difficult to fully install, configure and use. Make that NEVER. Use of github utils. should always signal a yellow alert for severe mal-use of English, but the lack of clear documentation for the use of gpg, kgpg, qtpass, zx2c4 (how does one even SPELL that???) and only then, passff makes this daunting, even for one with 12 years of linux experience and a masters degree in comp. sci. like I have.
Using password protected .odt file stored on a thumb drive to hold site logins and passwords is just as effective and much simpler. Makes this extension unnecessary, too.