For everyone else here who thought this had to do with Threads and wonder what Apple was thinking dealing with Meta like that:
Thread is a wireless smart home protocol designed to help your smart home devices talk to each other faster and more efficiently. Thread devices can connect to the internet and each other regardless of their brand and manufacturer. It is also the main infrastructure for Matter devices since it is designed with smart home meshes in mind. The more Thread-supported products you own, the stronger your smart home network becomes.