Validator standards + Bug in bug reporting

To the attention of Validator staff members.
I wanted to file a request about a behavior of Validator.nu shared engine
backend. I started by clicking on the "file a bug report" link, but it
brought me to a Bugzilla page with the following writing:
*"Sorry, either the product Validator (Nu) does not exist or you aren't
authorized to enter a bug into it.".*
I think that's because the product requested in the link parameters is
"Validator (nu)" while in the home page for bug reports, among the
products available for bug reporting, there is "Validator" rather than
"Validator (Nu)". The link should be set accordingly.
Anyway, the request I wanted to ask is: what are the standards which the
code is validated against? I thought it should be HTML5 Candidate
Recommendation, but from some reports I received (namely on the menu
element, already when it was present in the old structure in the CR) I see
that test pages are validated against HTML5.1 Editor's draft. Is it
correct? Shouldn't it be checked for errors with the most recognized
version of the spec, rather than the most recent?
Thanks in advance.
*Andrea*