[css-syntax] Concrete criteria for rule / declaration validity when being produced by a [compliant] parser? #10359
Description
parse-css implements certain criteria for determining if a rule is valid: https://github.com/tabatkins/parse-css/blob/c7859c41887409c533beed36956b7976ea0144b4/parse-css.js#L1142-L1167
Since the former was ostensibly written to verify the "soundness" of the current [CSS Syntax] draft, and because I don't see any of the implemented criteria specified in the draft, am I to understand these are specified in other CSS compendiums? A different module, perhaps?
If so, could one say that all CSS rules and declarations are syntactically valid as parsed? I am trying to assess how viable/useful it would be for a more general CSS parser to consider so, at the cost of qualified rules in the parse tree with e.g. a semi-colon (;) in their prelude, among other peculiarities.