^start of line
\d{4}a digit, repeated exactly 4 times
\/the literal / (4710 / 578 / 2F16)
\d{6}a digit, repeated exactly 6 times
?repeats the group contents below at most once:
\/the literal / (4710 / 578 / 2F16)
\d{3}a digit, repeated exactly 3 times
$end of line
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