Where Firefox for Android is keeping add-on generated files?

I want to find a folder, where Firefox for Android is keeping files generated by installed add-ons (list of saved tabs in OneTab, for example). I've tried to do a full root file system search (e.g. onetab.html, store.json) and looked insede specific app folders (e.g. /data/data/org.mozilla.firefox). Found nothing but the .xpi extension files. According to Help @ one-tab.com, tabs data is located in C:\Users\Username\AppData\Roaming\Mozilla\Firefox\Profiles\Profile Folder\jetpack\extension@one-tab.com\simple-storage\store.json for a Windows desktop version. On Android, using rooted Amaze, I've found nothing similar. Where should I search next? Are those files even visible for a root user?