Rated 5 out of 5 stars

per electro_rockets el feb. 4, 2016 · enllaç permanent

enter the advanced firefox settings:

1. in the address-bar type: "about:config"
2. press enter
3. click on: i'll be careful, i promise
4. locate the line: "xpinstall.signatures.required"
5. change its value from true to false

close the tab & rock on