\d+a digit, repeated at least once
\D+any character that's not a digit, repeated at least once
\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
\s*any whitespace character, repeated any number of times
\w+any word character, 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