I'm saying that usually comments are either wrong or out of date, developers code one regex, comment it, then fix a bug later and don't, then there's a discrepancy between the comment and the code. It's nearly always easier to just google the code and see what it does, if (as in this case) it's not obvious.
Google regex and you'll find plenty of resources including tools to testing patterns. You won't find much for any specific pattern but read the docs and it will be apparent what this regex does. Familiariy and competence with regex is a basic component of being a developer.
