\h*any horizontal whitespace character, repeated any number of times
#the literal # (3510 / 438 / 2316)
Negated Character Class[^:]+ +matches at least one character outside the set below:
:the literal : (5810 / 728 / 3A16)
:the literal : (5810 / 728 / 3A16)
\h*any horizontal whitespace character, repeated any number of times
g modifier: global. Finds all matches instead of stopping after the first