An anonymous reader writes: Mozilla today launched an iOS content blocker called Focus by Firefox. It's a "content blocker" because although Focus is capable of blocking some ads, this latest project from the non-profit is aimed at stopping trackers. The free app is made possible thanks to iOS 9's content-blocking feature, which requires some setting up. Like with any content blocker, after you download Focus, you'll have to activate Focus' content-blocking features within your system-wide iOS settings (launching the app will provide a guide to finish configuration). It's worth noting that Focus only works with Safari. Mozilla says, "This was not our choice—Apple has chosen to make content blocking unavailable to third party browsers on iOS." Here is the Focus GitHub repo and its feedback tool.