- Did they not apply?
- Did they apply but do not match the open source definition?
I found that the CERNOHL is also not listed.
The OSI only approves software licenses. The goal of the approval process is to determine whether the license provides software freedom and satisfies the Open Source Definition, which itself is a software-centric document.
The OSI does not review licenses with other subject matter, e.g. creative works, open data, or open hardware. While related, that is simply out of scope.
Especially with open hardware, there are also pretty fundamental reservations whether such licenses are enforceable. E.g. circuit schematics or 3D designs are not generally considered to be creative works that enjoy copyright protection. On which legal basis could a license then forbid use of the licensed material, or attach conditions? Other kinds of IP like patents or design patents come to mind, but they require prior registration and are highly jurisdiction-specific.
That effectively only leaves:
You note that hardware and software can sometimes be intertwined. The GPLv3 does have some provisions that apply when software is embedded into a physical “user product” (the anti-Tivoization clause).