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 always thought those were really cool! I used to have the launcher they made for Android on my old Droid Turbo, and it was pretty cool! Then it stopped working when I got a new phone with a newer version of Android.