I don't have direct knowledge, but I would guess that it is pulling follower/following data from multiple relays and if they disagree they do a venn diagram thing and just show what they can find across multiple relays.

I would actually love it if they could launch a full desktop app for Windows, Linux, Apple, etc that did not depend on a browser. I wonder if they are working on that. nostr:nprofile1qyxhwumn8ghj7mn0wvhxcmmvqyv8wumn8ghj7urjv4kkjatd9ec8y6tdv9kzumn9wsqzp4sl80zm866yqrha4esknfwp0j4lxfrt29pkrh5nnnj2rgx6dm622n97yv ? Possible?