http://starwars.wikia.com/wiki/Psychometry
^ I think the link through "The Force" was more with the holocron, since those are only accessible to Force-sensitive people. The saber just happened to be there with the holocron.
Kor
That's what I thought too, but looking at the scene he almost dismisses the holocron, while the sabre holds his attention even before he turns it on and realises what it is. Indeed, he flat out says "this thing wanted me to find it".
Then at the end of the episode when he walks away with the sabre (leaving the opened holocron behind, I might add) he has a vision of Kanan.
Now it's ambiguous as to whether that vision was actually Kanan directly communicating with him through the force, or if it was an actual force vision.
Taken at face value, the former would seem obvious alternative, but consider that we've never seen even (living) Jedi communicate that vividly and directly with one another, even over short distances. It's only ever been disembodied voices, projecting emotions and impressions. Luke to Leia, then Vader to Luke at Bespin and Yoda to Kanan & Ezra in the Lothal temple are probably the best examples.
Of note: the whole time in that scene, Ezra is holding the sabre in his hands.
I'm not saying it's definitive proof by any stretch, but it seems a reasonably strong possibility.
[ETA] It also occurs to me that perhaps Rey (and maybe Ezra to an extent) is just naturally gifted in
psychometry, much like Quinlan Vos.