?repeats the group contents below at most once:
\h*any horizontal whitespace character, repeated any number of times
\(the literal ( (4010 / 508 / 2816)
Negated Character Class[^)]+ +matches at least one character outside the set below:
)the literal ) (4110 / 518 / 2916)
\)the literal ) (4110 / 518 / 2916)
Non-Capturing Group(?:\h\w+)? ?repeats the group contents below at most once:
\hany horizontal whitespace character
\w+any word character, repeated at least once