(In reply to Milos from comment #16)
> Can somehow signing be disabled?
I don't think so if you are using Firefox 48+ on PC: https://wiki.mozilla.org/Add-ons/Extension_Signing#Timeline
However, on Firefox for Android (at least up to 66.0.2), you can set xpinstall.signatures.required to false and bypass this problem.
(In reply to Milos from comment #16)
> Can somehow signing be disabled?
I don't think so if you are using Firefox 48+ on PC: https:/ /wiki.mozilla. org/Add- ons/Extension_ Signing# Timeline
However, on Firefox for Android (at least up to 66.0.2), you can set xpinstall. signatures. required to false and bypass this problem.