[mfer]

Does Facebook Analytics for Apps segment the data from that of Facebook or combine it? Is there any policy even stated that says it's not used for other things. I would suspect, but have not looked, that all the data is combined together and used for selling ads and in other ways.

If that is the case, an app that is using it to get analytics for themselves is also sending lots of data to Facebook to be used for their other purposes.

Is this information transparent to anyone? This can lead to the tracking failing GDPR or other laws.

Now, if it was only analytics for apps for the benefit of the app owner and not shared... things might be different legally speaking.

Of course IANAL and they may have much more to say.