Can you locate any public or internal document that is on the internet or your intranet throughout your company? Once you get past a certain size, the Searchbox REST API makes that possible through access to its search services via the cloud or onsite. The API indexes raw content from a variety of sources.
Swipebuster is using the private Tinder API to obtain Tinder user data. Swipebuster can find out if a specific person is using Tinder and can provide the most recent date that person used the Tinder app. Other companies that have had private APIs reverse engineered include Uber, SnapChat, and Tesla.