$ curl "https://api.github.com/orgs/github"
{
  "public_gists": 0,
  "type": "Organization",
  "public_repos": 55,
  "url": "https://api.github.com/orgs/github",
  "blog": "https://github.com/about",
  "avatar_url": "https://secure.gravatar.com/avatar/...",
  "company": null,
  "login": "github",
  "email": "support@github.com",
  "followers": 674,
  "name": "GitHub",
  "created_at": "2008-05-11T04:37:31Z",
  "location": "San Francisco, CA",
  "id": 9919,
  "following": 0,
  "html_url": "https://github.com/github"
}

Note that url is not https://api.github.com/orgs/1 (or any numeral for that
matter). This holds the pattern of https://api.github.com/users/github

(I shortened the avatar_url link since it wasn't relevant.)

API actually returns status code 200.

So far, just from looking at commits on Pull Requests, it seems as if the
'author' and 'committer' fields are returning USER like data structures instead
of the structure that was there previously.

I'm not entirely sure yet that this is the response that is sent, but I'm
guessing that it is. I would have expected this to be documented, but I hope
this will get the attention of someone who can fix it if it isn't correct.