The spec is genuinely open (ucp.dev) - anyone can implement it without being a partner. Just publish a JSON file at /.well-known/ucp.

Built a free validator at ucptools.dev to check implementations. Tested several "partner" sites and almost no one has deployed it yet, including google.com (returns 404). The 60+ endorsements are just that - endorsements, not implementations.

colloquially known outside of the big business old pals act, as brown nosing.