Hey Folks.
Our Engineering team just wrapped up a large effort to make add-ons on Android work, but we realize there is still plenty left to do.
Please let us know about your developer experience around our Android support. Is there something missing you need for development, an API or some functionality that exists on Desktop that you cannot live without on Android?
Please share any feedback in the comments section - we value your input!
Ed Sullivan
Hello Ed! 
The one I miss the most is the storage.sync - to synchronize addons data between desktop and Android.
When this is implemented, I can release my “Private Notes” and “Send note to device” addons to Android.
Plus my already released “Auto Highlight” would also start to synchronize highlights with desktop which would be nice to have!
Thank you for your input!!
To port my Cast Kodi extension to Android, I need the API menus / contextMenus. The extension sends video links to the Kodi media player. The user right-clicks on the link, then selects Cast to Kodi in context menu.
To port Container Tab Groups we are developing, contextualIdentities API is needed. As soon as it becomes available, we will develop an Android version.
As a developer of two add-ons for organizing bookmarks, I would like to see the support of the Bookmarks API in Android. Especially Keep or Delete Bookmarks would work excellently on a smartphone in terms of user experience, as people are used to this concept from other popular apps. The user experience could be even more enhanced with swipe gestures for smartphone users, then it’s really the “Tinder way for organizing Firefox bookmarks”. 
It would be a fun project to implement for Android.
I confirm being able to use the contextMenu/menu API would be a real game changer. I maintain an addon allowing one to “clean up” links by removing any tracking code in it. Being able to long press a link and choose an action on it would be great!