(?m)applies the following effective flags to the remainder of the pattern: gm m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
^start of line
ifthe literal text if (case sensitive) .*any character (except for line terminators), repeated any number of times
\R+a newline sequence, repeated at least once
Non-Capturing Group(?:^[\t ]+.*\R+)*? *?repeats the group contents below any number of times:
^start of line
+matches at least one character from the set below:
\ta tab character (ASCII 9)
the literal (3210 / 408 / 2016)
.*any character (except for line terminators), repeated any number of times
\R+a newline sequence, repeated at least once
^start of line
+matches at least one character from the set below:
\ta tab character (ASCII 9)
the literal (3210 / 408 / 2016)
testthe literal text test (case sensitive) \.the literal . (4610 / 568 / 2E16)
checkthe literal text check (case sensitive) \(the literal ( (4010 / 508 / 2816)
\)the literal ) (4110 / 518 / 2916)
.*any character (except for line terminators), repeated any number of times
\R?optionally matches a newline sequence
g modifier: global. Finds all matches instead of stopping after the first