Firefox add-ons: how to install my own local add-on (extension) permanently in Firefox?

google-chrome firefox firefox-addon manifest browser-addons

Ran into the exact same problem the other day..

To get my personal xpi to install permanently (under Firefox for Linux 77.0.1):

had to disable extension signing about:config, xpinstall.signatures.required = false (unfortunatelly this will need to stay, because signatures seems to be verified on every browser start)
add an explicit id to browser_specific_settings section in the manifest

For example:

"browser_specific_settings": {  "gecko": {    "id": "blahblah@blah"  }}

Hope this helps!

google-chrome firefox firefox-addon manifest browser-addons

Did you try the web-ext tool and sign your add-on? You can use the Web-ext CLI tool to sign and install on your firefox.

CodeHunter