Mozilla did get Firefox for Android on Amazon App store as of version 9.0 (released way back in December 2011) however it was soon found out that Amazon modified and resigned the package and caused update problems as a result. This has not been resolved ever since apparently. Not sure if you can still side load the APK to install Firefox for Android on recent Amazon Fire tablets. https://archive.mozilla.org/pub/fenix/releases/133.0.3/android/ Fenix is the code name for Firefox for Android as to why folder name of fenix.