Perhaps a new section between 7 & 8 as follows;
The “ECMA” request header field is a number or text that indicates the client’s current ECMA implementation version. A blank ECMA hint would indicate that ECMA script is currently turned off.
ECMA = Text [32 ASCII characters]
If ECMA occurs in a message more than once, the last value should be used to override other occurrences. Examples;
#1 ECMA script is turned off ECMA: #2 ECMA script is on the Next version ECMA: Next #3 ECMA script is on version 5.1 ECMA: 5.1