It's nothing special, just a location tracker that logs to a file every so often based on time and/or distance moved (could also ping a URL with encoded location info instead). Basically the underlying data for location history without relying on Google. Its notable feature years ago was that it would do location 'steals' - instead of just triggering a then-expensive location check, it would grab the most current available location info as triggered by some other application and only force an update if that information was too old.

Don't make excuses for Amazon, please.