2.2.7 [XML] Section 3.1, Start-Tags, End-Tags, and Empty-Element Tags

C0007:

The specification states:

 Well-formedness constraint: No < in Attribute Values
 The replacement text of any entity referred to directly or indirectly in an 
 attribute value MUST NOT contain a <.

MSXML3 and MSXML6

Attribute values can contain the less-than sign ("<") if it is represented by either the < character reference or the < character entity reference.

C0008:

The specification states:

 Definition: An element with no content is said to be empty.] The representation of 
 an empty element is either a start-tag immediately followed by an end-tag, or an 
 empty-element tag. [Definition: An empty-element tag takes a special form:] 
 Tags for Empty Elements
 [44]   EmptyElemTag   ::=   '<' Name (S Attribute)* S? '/>'[WFC: Unique Att Spec]
 Empty-element tags may be used for any element which has no content, whether or not 
 it is declared using the keyword EMPTY. For interoperability, the empty-element tag 
 SHOULD be used, and SHOULD only be used, for elements which are declared EMPTY.

MSXML3 and MSXML6

Empty element tags are acceptable for any element that has no content, whether or not it is declared using the keyword EMPTY.