RSS feed format

I'm trying to use a feed from Debian that is apparently in an RDF format.
Also trying to use another from Gentoo and it's not being pulled in either.
This is the setup I'm using. The Gentoo and Debian are not being recognized for some reason.

The Debian feed header looks like this

<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet href="dsa-rdf.css" type="text/css"?>
<rdf:RDF

and the Gentoo one like this

<rss xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/" version="2.0">

Are those RSS feed formats not supported?

Well, since apparently no English speakers are familiar with this, I'll continue to update the thread with additional info as I come across it.
The Gentoo feed checks as a valid feed:

And the Debian does also: