Its value MUST be an Integer (Section x.x of
[I-D.ietf-httpbis-header-structure]), indicating a decimal number of
octets for a potential payload body.
"Decimal" is not a kind of number, but a way of representing it (as an alternative to e.g. binary, hexadecimal or octal). You can say it's an integer written in decimal form (but that is already part of the structured header's integer definition, and might be different in other serializations).
But the number of octets in a payload body is just an (integer) number, nothing decimal about it.
This also creates confusion because "decimal" is a separate type of structured-header item.
I would suggest to just remove the "decimal" here.
In section 2 of today's draft:
"Decimal" is not a kind of number, but a way of representing it (as an alternative to e.g. binary, hexadecimal or octal). You can say it's an integer written in decimal form (but that is already part of the structured header's integer definition, and might be different in other serializations). But the number of octets in a payload body is just an (integer) number, nothing decimal about it.
This also creates confusion because "decimal" is a separate type of structured-header item.
I would suggest to just remove the "decimal" here.