XML name characters

Tag and attribute names declared or referenced in any document processed by TopLeaf must use name characters located within the US-ASCII (7 bit) character range:

NameChar ::= Letter | Digit | '.' | '-' | '_' | ':'
Name ::= Letter | '_' | ':') (NameChar)*
Letter ::= [#x0041-#x005A] | [#x0061-#x007A]
Digit ::= [#x0030-#x0039]

This restriction also applies to TopLeaf tag and custom marker mappings. Custom marker names may not contain the colon character (‘:’).