Hi,
As I said, it wasn't me who added it and it works as it stands in all templates afaik. Looking at your suggestion though then I suspect it does work to recurse directories ( so a/** would match a/b and a/b/c/d/e ) and 'might' not be required but without some testing in all templates (including those deprecated) then I can't be sure that it wouldn't break something...
Thanks for raising it though and for all the work you've done and time spent finding bugs, I'll discuss it with some of the others.
Do you have a Github account? Why don't you fork the repo and fire us some pull requests?
John