With newer versions of firefox you can only temporarily load unpacked extensions. You need to re-add them if you relaunch firefox.
https://blog.mozilla.org/addons/2018/02/22/removing-support-...
https://blog.mozilla.org/addons/2018/02/22/removing-support-...
Both follow the WebExtensions-standard, so there’s not really much to “port”, if anything.