CDATA still does not allow you to include even arbitrary sequences of unicode codepoints, not to mention arbitrary binary data. On the other hand HTTP is in fa

CDATA still does not allow you to include even arbitrary sequences of unicode codepoints, not to mention arbitrary binary data. On the other hand HTTP is in fact a binary protocol and there is perfectly good way to transport sets of binary objects with associated metadata: MIME multipart/whatever. With multipart/byteranges even being part of HTTP itself and multipart/form-data being one of the "core web technologies".