DIFF (3)
- A server MAY return the difference in any format, however a server MUST minimally support the TBD difference format for all media types, and MUST perform Accept header processing of client diff format preferences.
- The server MUST minimally supply differences between two instances of the same media type, for all text media types encoded using the same charset. Ideally, servers will support differences between all media types, minimally providing an octet-level difference.