I think the npm doesn't support end of line comments, so

  ~/.npmrc
  min-release-age=7 # days 

EDIT: Actually maybe it does? But it's weird because

`npm config list -l` shows: `min-release-age = null` with, and without the comment. so who knows ¯\_(ツ)_/¯

ok, it works, only the list function shows it as null...