Which is why I use expanded regex with each section commented.
What is expanded regex?
They're likely referring to the \x modifier, also called extended regular expressions:
https://stackoverflow.com/questions/24642616/what-are-extend...
But I gotta say, regex isn't the best way to show things. Hard to verify, hard to maintain and what not. Computer sciency, sure. But not well "designed".
Now I have no love lost for people who talk about stuff without understanding the fundamentals or the basics even. So I don't doubt that the person was "whatever". But I do feel that regexes need an overhaul
Ps: I'm a fan too when I have to do quick stuff in shell. But not so much when I save it to a file to be read by me and multiple people weeks later. Regex is one thing that is way easier to write than read.