[KevBurnsJr]

There are 3 ways to use media types in web APIs. http://blog.kevburnsjr.com/domain-specific-media-types-and-r...

  0 domain specific media types    (application/json)
  1 domain specific media type     (application/vnd.github+json)
  many domain specific media types (application/vnd.github-issue.text+json, ...)

GitHub's v3 API uses the latter.