Firefox Focus is Mozilla's effort to make your internet experience a little more secure. Originally released in November 2016 for iOS, Focus blocks internet trackers, search history, anything that gets in the way of a clean, private browsing experience.
While those on Android have had to wait for their chance to use Focus, that wait hasn't gone unrewarded — Firefox has included some Android-only features in this release, possibly due to the fact that Android gives Firefox more ability to customize than iOS.
Android-specific features include an ad tracker counter, to see how many ads are blocked per site, the ability to disable the tracker blocker for sites that are not loading properly, and the option to have a notification sent when Focus is running in the background.
Mozilla seems dedicated to your security and privacy. There's even a default setting — Stealth — that disables screenshots. I had to do a little digging for it before I could grab these for this article. A little annoying for me, but hey, it shows Mozilla really cares.