New comment by silvernode on void-packages repository

https://github.com/void-linux/void-packages/pull/18077#issuecomment-572194695

Comment:
I guess it wants me to find the ID for this license, which there doesn't seem to be anything relevant on SPDX so I'll have to look into this and figure out what I need to supply to the string. Seems like I can just write"custom: proprietary" but I'm not sure.