atom:entry elements MUST contain an atom:summary element in either of the following cases:
- the atom:entry contains an atom:content that has a "src" attribute (and is thus empty).
- the atom:entry contains content that is encoded in Base64; i.e., the "type" attribute of atom:content is a MIME media type, but is not an XML media type, does not begin with "text/", and does not end with "/xml" or "+xml".
Ensure that there is at least a human readable summary or content for each entry.
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