Now it is confirmed that Tropic01 is open source with with open architecture, and it has transparent auditability.
It isn't fully open. Therefore it is closed (as any closed elements can poison the open ones).
I'm not sure what is meant by "transparent audibility". From their website they claim:
What sets TROPIC01 further apart from other chips is transparent auditability. TROPIC01 testing is led by experts, customers, and the open-source community to ensure verifiable trust and reliability, with public disclosure of results so that anyone can verify for themselves.
I'm not sure what this means in practice.