And makes it possible to justify retaining complex features that happen to be useful to many users. Knowing that a feature isn't used makes it easy to accurately remove crufty/complicated features without negatively impacting a lot of users. But in some cases features make app development more complicated (ALSA support in desktop firefox might be a better example, but I'm not super familiar with that case). to the toolbar if used a lot, or into a deeper menu if rarely used). Or whether moving it elsewhere is sensible (e.g. refresh pages a lot (or even, how can that data be sold)? OTOH it does let the developers know whether removing the refresh button would affect a lot of users.

but what nefarious things can one do knowing that some anonymous user happens to e.g. (The more interesting question is: could Focus receive the INSTALL_REFERRER itself for ads attribution instead of using Adjust? That data might be meaningless without asking google to tell you where it came from, and they provided it in the first place anyway.) This is the only time play-services-analytics shuld be used, i.e. This only comes into play if you install the app from the play store (which funnily enough Google own). Adjust depends on play-services-analytics. This is only used to determine whether the app was installed as the result of a specific (google-hosted) ad campaign. Adjust SDK: an install attribution tool (aka install referrer tracking). This stuff is used for deciding what features to prioritise (or remove), and doesn't involve Google servers. do people use share, do people use custom tabs, do people clear using the bin button or the notification). This only sends data to Mozilla servers, and only concerns what features people use (i.e. Mozilla telemetry: enabled by default in Focus, disabled by default in Klar.

Focus (for Android) doesn't use Google analytics directly, but it's an indirect dependency - see below.

Incognito firefox focus