Error Message Feedback - css linking close tag

Validating http://gatoatigrado.existhost.com/

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It appears that the <link> tag is not supposed to have a self-closing / -
i.e. <link rel="stylesheet" type="text/css" href="___.css" />. This doesn't
follow XML syntax - is this supposed to be a special exception?

If there is a valid reason why this is so, please adjust the output of the
validator so that it says something more meaningful than "head not closed".
If you want, validate my page with it; I didn't correct it yet as it
displays fine in most browsers.

Thank you for your effort, you have made the web a much better place.

Nicholas