?repeats the group contents below at most once:
\+?optionally matches the literal + (4310 / 538 / 2B16)
\d+a digit, repeated at least once
\s?optionally matches any whitespace character
?repeats the group contents below at most once:
\(the literal ( (4010 / 508 / 2816)
\d{2}a digit, repeated exactly 2 times
\)the literal ) (4110 / 518 / 2916)
\d{4,5}a digit, repeated between 4 and 5 times
-the literal - (4510 / 558 / 2D16)
\d{4}a digit, repeated exactly 4 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