Adding the Sendmail license

Hello there. I help maintain OpenDKIM and OpenDMARC. These use the Sendmail license, partially because much of their code was developed at Sendmail Inc by Sendmail employees. There are subsequent licenses that some of our code is covered by, but at least a large portion of the code will still be covered by the sendmail license as well.

Additionally, Sendmail and other sendmail-originated things like libmilter exists inside several other open source projects (many of the BSD's for example), and the LICENSE.sendmail file appears alongside that code. Doing a code search as per your site showed about 2000 hits.

This is an *old* license. It's well proliferated. Nobody is licensing NEW software with it anymore, but having GitHub show "Unknown license" for this feels broken.

None of opendefinition.org, gnu, or opensource.org list this license, but this feels like simple oversight.

Also, as I am not a sendmail employee, I don't even know that I can apply for the license to be approved by these bodies.

What's the best way to proceed here?