Q the literal text Q (case sensitive) \da Unicode decimal digit
\.the literal . (4610 / 568 / 2E16)
the literal (3210 / 408 / 2016)
.*?any Unicode character, repeated any number of times
Positive Lookahead(?=\n\nQ \d\.|$) 1st Alternative\n\nQ \d\. \na line-feed (newline) character (ASCII 10)
\na line-feed (newline) character (ASCII 10)
Q the literal text Q (case sensitive) \da Unicode decimal digit
\.the literal . (4610 / 568 / 2E16)
$end of string, or before its final line terminator
s modifier: single line. Allows a dot to match line terminators
g modifier: global. Finds all matches instead of stopping after the first