_rev: 5-xxx
_revisions:
    start: 5
    ids:
        - xxx
        - xxx
        - xxx
_attachments:
    foo.txt:
        content_type: text/plain
    bar.txt:
        content_type: text/plain
        revpos: 4
    baz.txt:
        content_type: text/plain
        revpos: 3