Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
I completely forgot Firefox had a phone.
Facebook has phones too back then, though they're just Android with Facebook button.
Not long before Amazon came out with their spyware phone.
Seriously - they bragged about how the Fire Phone was always spying on you and still tried to charge $600 for it. Like three months later, they had to discount it to $99 and include a year of Prime.