BNF syntax in RDFa Core 1.1

What form of BNF is used in the grammar productions in the 
RDFa Core 1.1 spec?  It's possible I'm missing something, 
but I cannot see it stated.  My undestanding is that most 
XML-based standards use, explicitly or more frequently 
implicitly, the form of Extended BNF defined in §6 of the 
XML specification (either 1.0 or 1.1).

However that isn't the case in RDFa Core 1.1, e.g. in §6, 
there's the production:

   curie  ::=  [ [ prefix ] ':' ] reference

The use of square brackets for productions that optionally 
occur is not allowed in XML's EBNF which would have this 
rule expressed thus:

   curie  ::=  ( prefix? ':' )? reference

More confusingly, the definition of 'reference' in §6 
uses a '/' to denote alternatives, while the definitions of 
'whitespace' in §5.2 and 'termChar' in §7.4.3 use '|'.

My best guess is that the grammar productions in §5 and §7 
are using XML's EBNF, while those in §6 'CURIE Syntax 
Definion' are written using IETF's ABNF as defined in RFC 
2234.

There's a certain logic to this.  Things relating to URLs 
are generally expressed in ABNF because most of the 
standards are IETF RFCs; things relating to XML are 
generally expressed in EBNF because most of the standards 
are W3C Recommendations.  So it made sense for the 'CURIE 
Syntax 1.0' note to use ABNF.  But now that this has been 
folded into the RDFa Core spec, it seems confusing to have 
both BNF syntaxes in use in the same document.

Can I suggest that an errata is issued, either to convert 
the four productions in §6 to use XML's ENBF, or to add a 
note to the document stating that §6 uses ABNF while the 
result of the document uses EBNF?


Richard