Non-Capturing Group(?:\s+)? ?repeats the group contents below at most once:
\s+any whitespace character, repeated at least once
\w+any word character, repeated at least once
\?the literal ? (6310 / 778 / 3F16)
.any character (except for line terminators)
\s+any whitespace character, repeated at least once
\w+any word character, repeated at least once
Non-Capturing Group(?:\[\])? ?repeats the group contents below at most once:
\[the literal [ (9110 / 1338 / 5B16)
\]the literal ] (9310 / 1358 / 5D16)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string