\Gstart of current search
\p{Lu}+an uppercase letter, repeated at least once
\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match
+matches at least one character from the set below:
.the literal . (4610 / 568 / 2E16)
\hany horizontal whitespace character
Negative Lookahead(?!\p{Lu}\p{Ll}) \p{Lu}an uppercase letter
\p{Ll}a lowercase letter
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