A tagline, slogan, or other short description of the feed.
If this contains HTML or XHTML, it is sanitized by default.
Comes from
- /atom:feed/atom:tagline
- /rss/channel/description
- /rss/channel/dc:description
- /rdf:RDF/rdf:channel/rdf:description
- /rdf:RDF/rdf:channel/dc:description