I'm tempted to call it less rigorous, but it seems more likely an expression of a different philosophy. Is that right? (In case it wasn't clear: I don't even know what to type into DuckDuckGo at this stage.)
@jorendorf As a student of ECMAScript/HTML reading the CommonMark spec, I'm struck by how differently they've taken to specify the language. No algorithms, no grammar, just descriptions of the expected behavior.