Atom feed validation question.

Greetings:

I'm struggling with a validation issue using the w3 validator to check
documents created by my atom 1.0 feed  generator library

>From the atom spec
http://atomenabled.org/developers/syndication/atom-format-spec.php

atomCommonAttributes = attribute xml:base { atomUri }?, attribute xml:lang {
atomLanguageTag }?, undefinedAttribute*

and

undefinedAttribute = attribute * - (xml:base | xml:lang | local:*) { text }

I'm interpreting undefinedAttribute as an attribute that  does not start
with xml:base, xml:lang or xmlns:... .

I am also interpreting that atomCommonAttributes can have any number of
undefinedAttributes in them.

Does this mean that any element which can contain an atomCommonAttribute
(Logo for example)  validate with an arbitrary attribute?

The http://validator.w3.org validator does not seem to work this way but I
am looking for some kind of explanation or insight as to why this Logo links
does not validate:

The feed can be found here http://www.earthbeats.net/drops.xml and the
validator shows the following line to be in error (and also the icon
element).

<logo href="http://www.earthbeats.net/drops.xml"
rel="self">http://www.earthbeats.net/images/catalogue.gif</logo>

It contains the href and rel attributes which I think fall into the
undefinedAttribute category, but the feed does not validate.

Thanks for your comments or feedback.

Bill.