Yes, it's NIP-66, unfortunately the video didn't loaded a good relay monitor (i am just selecting the first monitor to appear), but the idea is to show you the people you follow what relays they are part of sorted by the number of people.
I haven't tried dev, but here's a quick video I recorded with some things I noticed:
https://coracle-media.us-southeast-1.linodeobjects.com/nosotros.mov
Yes, it's NIP-66, unfortunately the video didn't loaded a good relay monitor (i am just selecting the first monitor to appear), but the idea is to show you the people you follow what relays they are part of sorted by the number of people.
Ah, nice, that screenshot makes it make a lot more sense