\Gstart of current search
Non-Capturing Group(?:(?! X ).)*? *?repeats the group contents below any number of times:
Negative Lookahead(?! X ) X the literal text X (case sensitive) .any character (except for line terminators)
\ban ASCII word boundary
\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match
\d+a digit, repeated at least once
Athe literal A (6510 / 1018 / 4116) (case sensitive)
\ban ASCII 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