You can have more info about that at https://developer.mozilla.org/en-US/Add-ons...

You can have more info about that at https://developer.mozilla.org/en-US/Add-ons/Firefox_for_Andr... but be aware that Mozilla is moving its extension development system to WebExtensions which are different than the current system. You can check more about WebExtensions at https://developer.mozilla.org/en-US/Add-ons/WebExtensions

This movement towards WebExtensions will take some time and new APIs are being developed as they figure out the needs of the developers. WebExtensions are easier to write and make them cross-platform (Firefox OS, Firefox for Android, Chrome...). It might not be ready now but its a good thing to check out.