Negative Lookbehind(?<!\d) \d{4}a digit, repeated exactly 4 times
-the literal - (4510 / 558 / 2D16)
\d{2}a digit, repeated exactly 2 times
-the literal - (4510 / 558 / 2D16)
\d{2}a digit, repeated exactly 2 times
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters
g modifier: global. Finds all matches instead of stopping after the first