Mime type of the content, with charset etc.
Date attachment was first created
Data inline, base64ed
Additional Content defined by implementations
Hash of the data (sha-1, base64ed)
xml:id (or equivalent in JSON)
Human language of the content (BCP-47)
Number of bytes of content (if url provided)
Label to display in place of the data
Uri where the data can be found
Generated using TypeDoc
Content in a format defined elsewhere