Non-Capturing Group(?:\G(?!^)|^(?!a)) \Gstart of current search
^start of line
athe literal a (9710 / 1418 / 6116) (case sensitive)
\D*any character that's not a digit, repeated any number of times
\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
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