Message

QueryRequest Identifier value MUST be expressed in a UUID syntax (RFC 4122).

Context
query:QueryRequest
Test
matches(normalize-space(./@id), '^[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}$')
Usage
/ query:QueryRequest