XDJ-700 Star Rating & Rekordbox Button

On the 700 there is a Rekordbox button above the USB and Link buttons on the left hand display.
What does this actually do??
I’ve never gotten it to work, even when the deck was connect to rekordbox.

Also when I’m playing tracks. I’d love to edit and change The “Star Rating”
I notice if I click the info button there is a little pencil next to stars but I’ve never managed to edit the star rating at all.
Is it possible to do this on the 700??

Many thanks!