Lol! It's very similar. They both are UNIXlike systems. OpenBSD is very much its own implementation of UNIX though. It is maintained by a private, globally distributed community of developers who use the OS as their daily driver and have a strong inventive to keep it extremely secure, modular, configurable, and just generally very UNIX philosophy compliant.
They have a commitment to being politically neutral and to not utilizing copyright laws for any purpose whatsoever beyond the very basic attribution of authorship and inclusion of the permissive license & disclaimer:
https://cvsweb.openbsd.org/src/share/misc/license.template?rev=HEAD The fact that they are not captured by ideology says a lot about the focus and security of that community, as opposed to the GNU community which heavily relies on the U.S. government and believes that freedom comes from fiat (an obvious contradiction to us).