Look, I’m an author of this mozilla add-on for rare cases, it has small user base, but it’s got a solid 4.7 star rating.
https://addons.mozilla.org/en-US/firefox/addon/bulk-stored-password-changer/
http://karasik.eu.org/misc/addon2.png
Now, avast scans it and says nasty things, “unreputable”, “poor rating”, 2 stars:
http://karasik.eu.org/misc/addon.png
Well f**k you too, avast, this is a bloody shame to smear small software like this.