\[the literal [ (9110 / 1338 / 5B16)
\s*any whitespace character, repeated any number of times
\d+a digit, repeated at least once
\.*the literal . (4610 / 568 / 2E16) , repeated any number of times
\d*a digit, repeated any number of times
\s*any whitespace character, repeated any number of times
\]the literal ] (9310 / 1358 / 5D16)
\s+any whitespace character, repeated at least once
Non-Capturing Group(?:\d+\.\s*)? ?repeats the group contents below at most once:
\d+a digit, repeated at least once
\.the literal . (4610 / 568 / 2E16)
\s*any whitespace character, repeated any number of times
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