\d{1,2}a digit, repeated between 1 and 2 times
/the literal / (4710 / 578 / 2F16)
\d{2}a digit, repeated exactly 2 times
Non-Capturing Group(?:/\d{4})? ?repeats the group contents below at most once:
/the literal / (4710 / 578 / 2F16)
\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