Until Greg gets it signed:
To get a Firefox Add-on signed:
1. Open the Add-on's .xpi installation file with WinRAR or a similar program.
2. Open install.rdf
3. It should be enough to change just one character in value <em:id>
5. Change the maximum
Firefox version the add-on supports to three versions after the current version.
So if the current
Firefox version is 43, change this value to 46.0:
<em:maxVersion>46.0</em:maxVersion>
It is not possible to go higher than three versions ahead of the current version, meaning this process will have to be repeated every three incremental versions of Firefox.
6. Save the edited install.rdf and make sure that .xpi archive is updated with the changes.
7. Go to
https://addons.mozilla.org/ Sign in Tools > Submit a New Add-on > CHECK: Do not list my add-on on this site > Select a file... > browse to the edited .xpi file > Open > Continue > Enter the name you choose for the edited file > Continue >
Click on where it says "You can download it here:"
**IMPORTANT**
Download the file from this page, and delete the edited file from your computer.
This is because the one on your computer has not been signed, and the one listed on this page now, has an embedded signature.
8. Finally, after you install the signed Add-on, the old one will still remain installed on Firefox, so you need to manually uninstall the old one.