Bug in Schema for XSLT 2.0?

Hello,

I think I found a bug in the non-normative Schema for XSLT 2.0 at
http://www.w3.org/2005/02/schema-for-xslt20.xsd

This snippet is from there:

<xs:complexType name="text-element-base-type">
  <xs:simpleContent>
    <xs:restriction base="xsl:versioned-element-type">
      <xs:simpleType>
        <xs:restriction base="xs:string"/>
      </xs:simpleType>
      <xs:anyAttribute namespace="##other" processContents="lax"/>
    </xs:restriction>
  </xs:simpleContent>
</xs:complexType>

It is a complexType with a simpleContent, but the specified
"versioned-element-type" does not have simple content.
But changing the second line (<xs:simpleContent>) to complexContent does not
resolve the problem, because as I know, you cannot have a simpleType definition
inside a restriction. Am I right?
For me it is also not really clear, what this simpleType inside the restriction
should mean.

regards,
Peter