is the kind of things this forbids. Most peoples parsers would ignore this as a comment (if we have comments), but maybe some would do it in a special way. Either everyone ignores the comments in the parser (this is unlikely to carry on for long, someone will want to extend it) or nobody is allowed comments. That way everyone parses the same text.
Which is fine, because it's in a format that everyone can parse. Adding
is the kind of things this forbids. Most peoples parsers would ignore this as a comment (if we have comments), but maybe some would do it in a special way. Either everyone ignores the comments in the parser (this is unlikely to carry on for long, someone will want to extend it) or nobody is allowed comments. That way everyone parses the same text.