Two (very quick) minutes on their GitHub repo and it's pretty obvious that they're using firebase-analytics and at the very least seem to be sending URLs[1] and infos such as the model you download or the capacities[2] you use.
[1] https://github.com/google-ai-edge/gallery/blob/main/Android/...
[2] https://github.com/google-ai-edge/gallery/blob/main/Android/...