I just learned about it recently when I posted about a road trip I'll be taking next month. Here is a link that explains it all:
https://rowbyrowexperience.com/rxr-program-page/
Basically, each participating shop has a pattern you can collect for free, which would be one row of a final quilt. You can just collect the patterns (looks like the theme changes each year) to make a quilt, or you can compete in a contest-- be the first to complete a quilt and present it to a participating store and win a pile of fat quarters.
I have no desire to compete, but am looking forward to being able to pick up some free patterns this year. I got my first one at Cool Cottons in Portland, OR, on Sunday, which has windchimes with mountains on the bottom.