Matrix.org hosts Mozilla’s Matrix server. Further, the way all data is synced to all servers means if someone with a Matrix.org ID joins your room (which is most users), all data is synced to the home server. Almost all of the data is in Matrix.org’s possession & with the servers being as expensive as they are to run, more orgs shutdown when popular causing users to flock to the mother instance.
In this case that would be Mozilla, not the host
Matrix.org hosts Mozilla’s Matrix server. Further, the way all data is synced to all servers means if someone with a Matrix.org ID joins your room (which is most users), all data is synced to the home server. Almost all of the data is in Matrix.org’s possession & with the servers being as expensive as they are to run, more orgs shutdown when popular causing users to flock to the mother instance.