Also, you’re going to need to update the IANA considerations to include the other values needed in the registry:
Value, which is a number between 0 and 2039.
** Just don’t pick 8 since that’s already been used.
Flag Name, which is a string
Message, which like the "TLS 1.3" field in the ExtensionType
registry contains the abbreviations of the messages that may
contain the flag: CH, SH, EE, etc.
Recommended, which is a Y/N value determined in the document
defining the optional feature.
Reference, which is a link to the document defining this flag.
From Sean T: