No, xmpp.org is the XMPP Standards Foundation. The Modern XMPP project is a separate initiative.
Well, as separate as can be - I'm heavily involved in the XSF as well. But the XSF is focused on matters of protocols, and it grew increasingly clear to me that we needed a less official space for collaborating on non-protocol issues such as user interfaces.
This Mastodon instance is for people interested in technology. Discussions aren't limited to technology, because tech folks shouldn't be limited to technology either!