This 'fp' thing when copying stuff in hookpad

In C major if you copy a I chord that is placed at the very start of the project, you get this:

{"notes":[],"chords":[{"root":1,"beat":1,"duration":4,"type":5,"inversion":0,"applied":0,"adds":[],"omits":[],"alterations":[],"suspensions":[],"pedal":null,"alternate":"","borrowed":"","isRest":false,"recordingEndBeat":null}],"fp":"5307dd13134f5f800e14df3395a5f52525b44c07"}

Most of them seem self-explanatory except for the ‘fp’ at the end. Can someone tell me what that is

fp is short for fingerprint. It is a way for us know the data has not been manipulated between copy and paste operations.