Why do you not have a home button? Seriously. The 3rd party addon stopped working which is another story but the question remains- why does it not have one?
Every forum suggest installing this 3rd party home button addon which I did. Subsequent to one of the FF updates it stopped working, it changes all my tabs to "about:home" thereby rendering my open pages gone unless I dig through my history. Garbage. I've given feedback to the addon Dev but the simple solution would be for Firefox to just give users the option to have a home button. I dealt with this for like a year and a half not knowing what the issue was until I finally got fed up and uninstalled FF Android. I almost switched browsers because an addon that produces what should be a basic function had stopped working- Firefox should just have a bloody home button option.