Discover the exciting new features of TeamSpeak 6, including a complete redesign, screen sharing capabilities, and community server management, all aimed at improving user experience in gaming communication.
no, it means there's no central server. You still need a Matrix server to handle communications, but there's no "central matrix server", the servers discover each other based on a baked-in "known good" server list + ad-hoc discovery (e.g. if a server has a group chat with a member of a server your server doesn't know yet, and you join that group chat, your server and the unknown one exchange metadata and so on).
Federated means that different servers can talk to each other and decentralized means that there is no server.
There is also nothing stopping someone from using the Matrix protocol to create another service, though I don't know of one that exists.
no, it means there's no central server. You still need a Matrix server to handle communications, but there's no "central matrix server", the servers discover each other based on a baked-in "known good" server list + ad-hoc discovery (e.g. if a server has a group chat with a member of a server your server doesn't know yet, and you join that group chat, your server and the unknown one exchange metadata and so on).
You just described federation.
No, this is called decentralisation.
Federation would be the exchange of rules, policies, blocklists, etc., beyond the ability of servers to talk to each other.