f1131623_sion_Reference__Special_Groups__Description
[Feature] Comment [Syntax] (?#comment) [Example] a(?#foobar)b matches ab [JGsoft] YES [.NET] YES [Java] no [Perl] YES [PCRE] YES [PCRE2] YES [PHP] YES [Delphi] YES [R] YES [JavaScript] no [VBScript] no [XRegExp] YES [Python] YES [Ruby] YES [std::regex] no [Tcl ARE] YES [POSIX BRE] no [POSIX ERE] no [GNU BRE] no [GNU ERE] no [Oracle] no [XML] no [XPath] no [Description] 
Everything between (?# and ) is ignored by the regex engine.
Regular Expression Reference: Special Groups