Society & Culture
Amazon FireOS is a fork of stock Android. And what must be remembered it is it has to support a lot of software repo's and a lot of older libraries. However Amazon not licencing Android from Google and not partaking in the Play ecosystem is one matter. Amazon have only got to support a limited range of graphics chipsets and a limited range of hardware mainboards so it's NOT a lot of work. There are mainstream open source Linux distributions supporting PPC Intel ARM who have to do a lot more work than Amazon.
Amazon FireOS tablets have always been two to three distributions behind Google. Have always failed to have security standards aligned with Google. No file encryption or SD card encryption. No Knox equivalent etc. So you'd expect if you have older stable dev trees that you would take security and privacy seriously.
I proved categorically that Amazon did no such thing