https://github.com/dolphin-emu/dolphin/blob/master/Source/Co... is the actual code which collects most of the information. We do multiple things to avoid being able to track user activity too much -- for example, while every instance of Dolphin has a unique ID so we can do things like unique counts, events that happen within a play session are associated to truncated_hash(unique ID + game ID) and not directly with the unique ID. This means that we can only correlate events from the same user playing the same game, but not* two events from one user playing different games.

* Our implementation is a bit weak given that the set of all gameids is small and enumerable. We could probably do better there.