It's a matter of taste whether http://www.ietf.org/ID-Checklist.html
is obscure or not, but it is quite explicit and cites RFC 2434
which is BCP 26.
BCP 26 says, among other things:
All future RFCs that either explicitly or implicitly rely on the IANA
to register or otherwise manage assignments MUST provide guidelines
for managing the name space.
The IESG operates on this basis. It's true that it isn't enforced at
I-D submission time; but it is enforced in IESG review.
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