graph-facebook-com/app/activities is an endpoint used by 3rd party developers working with Facebook SDKs to send app analytic data for insights.
https://developers.facebook.com/docs/marketing-api/app-event... http://www.facebook.com/analytics https://business.facebook.com/events_manager/app/events
This is what a URL can look like.
graph-facebook-com/1106907002683888/activities?method=POST&event=MOBILE_APP_INSTALL&anon_id=1&advertiser_tracking_enabled=1&application_tracking_enabled=1&custom_events=[{%22_eventName%22:%22fb_mobile_purchase%22,}]
If you click the above you'll litter my analytics feed for my app 1106907002683888 with junk data.
Just in case, someone was looking for the specific call talked about because I couldn't find it linked in Vice's article.