What is the issue with the HTML Standard?

From @sideshowbarker

I notice the index doesn’t seem to include entries for the headingoffset and headingreset global attributes.

And further, the spec doesn’t state any document-conformance requirements about the allowed values of those attributes — that is, it should rightly explicitly state somewhere that they are non-negative integer (headingoffset) and boolean (headingreset). (Which can be inferred from the implementations requirements, but should also be stated explicitly somewhere.)