HTML5 custom meta element name attribute values should be a warning

While validating some HTML Doctyped as HTML5 with the W3C Markup Validator
(http://validator.w3.org), I came across the following error:

Line 6, Column 35: Bad value version for attribute name on element meta:
Keyword version is not registered. 

<meta name="version" content="1.0">

Line 7, Column 52: Bad value support-email for attribute name on element
meta: Keyword support-email is not registered. 

<meta name="support-email" content="test@email.com">

 

I believe this is the relevant section of the HTML5 spec:
http://www.whatwg.org/specs/web-apps/current-work/multipage/semantics.html#o
ther-metadata-names

 

When I validate using the HTML 4.01 Strict Doctype, the errors aren't there.
Is there a reason that this warrants an error instead of a warning?  Is this
an issue with the HTML specification(s) or with the W3C Validator?

 

The test HTML that I was validating:

<!DOCTYPE html>

<html lang="en">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

<meta name="author" content="FirstName LastName">

<meta name="version" content="1.0">

<meta name="support-email" content="test@email.com">

<title>Title Here</title>

</head>

<body>

<p>Hello World!</p>

</body>

</html>

 

Thank you,

Ryan Foster

Received on Monday, 8 August 2011 14:38:44 UTC