Modify other persons extension and sign under my account

Occasionally, with the old un-signed FF extensions I would make small modifications to someone else’s extension (ie change the hot key, the menu it appeared under, or use an icon that matched my theme).

Wondering if I could do this now and resubmit it under my developer account to be signed? This modified extension would only be for personal use and not redistributed or listed in publicly.

Will this will create any issues.

Two thoughts:

(1) Does the license or applicable law allow modification? Beyond the scope of this forum, probably.

(2) If the manifest.json file contains an extension ID, you probably need to change or remove it.