Now that we agree on that, why should there be a
specification for (a)
and one that does (a)+(b)? Wouldn't it be both easier and cleaner if
the specification that does (b) would not also have (a), if we have an
independent specification for (a) anyway?
Well partly because I don't think we want b without a to be a thing you can
do. But also because it's so cheap to have begin/end attributes. If the app
also supports other ways of doing a it can consider them redundant.