#Sectionthe literal text #Section (case sensitive) \d+a digit, repeated at least once
Non-Capturing Group(?:(?!#Section\d).)* *repeats the group contents below any number of times:
Negative Lookahead(?!#Section\d) #Sectionthe literal text #Section (case sensitive) \da digit
.any character (except for line terminators)
\ba Unicode word boundary
Jack/M,the literal text Jack/M, (case sensitive) \d+a digit, repeated at least once
\h+any horizontal whitespace character, repeated at least once
\d+a digit, repeated at least once
Non-Capturing Group(?:\.\d+)? ?repeats the group contents below at most once:
\.the literal . (4610 / 568 / 2E16)
\d+a digit, repeated at least once
\ba Unicode word boundary
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