Have an app I wrote that I needed altitude from. Remarkably, searches for altitude in the documentation for iOS turns up very little. It‘s a property in CLLocation, and it is fetched by the LocationManager, but for whatever reason, it seemed it was always 0. The course to solving this mystery is worth documenting because it touches on a lot of pieces that have been covered here before: documentation, heuristics, the process of coding by just filling in blanks rather than following logical procedural pathways, etc. Along the way, there are also some very interesting design considerations.