Comment 15 for bug 2042902

I contacted Ethan who created the one patch I could not track down.
He had all the information that I needed:
- This is actually from
  - https://github.com/alsa-project/alsa-ucm-conf/pull/321
  - https://github.com/alsa-project/alsa-ucm-conf/pull/322
- related to private LP bug 2037058
- Not yet upstream accepted, but discussed with sil2100 and accepted
  as-is for now
- Ethan plans to file a public LP and update it once upstream accepted
  a final form of it

I'll put all of that into the patch headers to help the next person that
comes by.