I never even thought to look in the Help menu. Since the Action help now takes us directly to the wiki, I think a reasonable expectation is that the wiki should be comprehensive. Am I wrong in thinking this?
Seems like a link to it should be on the major RegEx wiki pages.
I did search the wiki for every form of regular expressions, and it did not return "ICU Regular Expressions Reference"
This reference says:
The regular expression patterns and behavior are based on Perl's regular expressions.
This is the information we need we comparing with other sources on the Internet, and other RegEx tools.