(?-s)applies the following effective flags to the remainder of the pattern: gm s modifier: -single line. A dot does not match line terminators such as \n
^start of line
.+any character (except for line terminators), repeated at least once
\R?optionally matches a newline sequence
\ban ASCII word boundary
\d{2}a digit, repeated exactly 2 times
\.the literal . (4610 / 568 / 2E16)
\d{2}a digit, repeated exactly 2 times
\ban ASCII word boundary
%the literal % (3710 / 458 / 2516)
Positive Lookahead(?=((?:\R^.+){2})) Non-Capturing Group(?:\R^.+){2} {2}repeats the group contents below exactly 2 times:
\Ra newline sequence
^start of line
.+any character (except for line terminators), repeated at least once
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