RSS 2.0 Specification
https://cyber.harvard.edu/rss/rss.html
XML namespace
| name | source | namespace |
| DF Site Summary 1.0 Modules: Content | http://purl.org/rss/1.0/modules/content/ | content |
| DCMI Metadata Terms | http://purl.org/dc/elements/1.1/ | dc |
| Media RSS | http://www.rssboard.org/media-rss | media |
