None of those seem much easier to understand than the others. I suspect this is a classic example of "let's take something that is really messy in pcre and comp

None of those seem much easier to understand than the others. I suspect this is a classic example of "let's take something that is really messy in pcre and compare it other more brief equivalents" but I could easily turn the regex into something more readable and I can find more help for the standard regex syntax than I can for any alternative. As other's have said, it is a minor arguably cosmetic improvement and something that is likely easier just to use a visual helper like regex101 to help you construct.