Only what’s in TFA itself, though it could have been made clearer:
Kylo Ren mentions that the First Order only partially recovered the map to the first Jedi Temple from the old Imperial archives.
BB8 suggests perhaps R2 has the rest of the map, which 3PO immediately poo-poos. But, inspired by the idea, he starts searching his memory. He does eventually find it, acquired when he plugged into the Death Star in ANH.
Nothing to do with Rey, and not sone bread crumb Luke left in order to be found.