\Sany non-whitespace character
.*?any character (except for line terminators), repeated any number of times
\.the literal . (4610 / 568 / 2E16)
"?optionally matches the literal " (3410 / 428 / 2216)
Positive Lookahead(?=\s|$) \sany whitespace character
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