?repeats the group contents below at most once:
NFthe literal text NF (case sensitive) \s?optionally matches any whitespace character
ENthe literal text EN (case sensitive) \s?optionally matches any whitespace character
ISOthe literal text ISO (case sensitive) \s?optionally matches any whitespace character
\d{3,6}a digit, repeated between 3 and 6 times
?repeats the group contents below at most once:
:?optionally matches the literal : (5810 / 728 / 3A16)
\d{1,4}a digit, repeated between 1 and 4 times
-?optionally matches the literal - (4510 / 558 / 2D16)
\d?optionally matches a digit
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