A Conformant Mechanism for Content Binding in Text Streams

This document proposes a conformant mechanism for binding metadata to plain text streams using boundary-delimited transport. The mechanism uses existing ASCII characters to establish a text/non-text boundary, requiring no new code points and no changes to existing Unicode text processing algorithms. It defines a delimiter format, a parsing algorithm, a canonicalization procedure, and correctness criteria sufficient for two independent implementations to interoperate without coordination. This RFC is a companion to a Unicode Technical Standard proposal submitted to the Unicode Technical Committee.