Product-friendly licensing

OpenBSD's has extremely stringent licensing standards
Comprehensive licensing audit
Bulk of the code is BSD licensed
Much is 2 or 3 clause BSD
New code targeting ISC-style license
(equivalent to 2 clause BSD)
GPL code is clearly identified (and constantly diminishing)

What does this mean?
You can ship the whole OS as part of your product if you want
Applications developed on OpenBSD can be "applianced" trivially
No "hidden functionality" binary components