Rewrite abstract as proposed

draft-ietf-rats-uccs.md

@@ -90,8 +90,15 @@ entity:
 
 --- abstract
 
-When transported over secure channels, CBOR Web Token (CWT, RFC 8392) Claims Sets may not need the protection afforded by wrapping them into COSE, as is required for a true CWT.
-This specification defines a CBOR tag for such unprotected CWT Claims Sets (UCCS) and discusses conditions for its proper use.
+This document defines the Unprotected CWT Claims Set (UCCS), a data format for
+representing a CBOR Web Token (CWT) Claims Set without protecting it
+by a signature, message authentication code (MAC), or encryption.
+UCCS enables the use of CWT claims in environments where protection is
+provided by other means, such as secure communication channels or
+trusted execution environments.
+This specification defines a CBOR tag for UCCS and describes the UCCS
+format, its encoding, and processing considerations, and discusses
+security implications of using unprotected claims sets.
 
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