+repeats the group contents below at least once:
\s*any whitespace character, repeated any number of times
\|the literal | (12410 / 1748 / 7C16)
\s*any whitespace character, repeated any number of times
\w+any word character, repeated at least once
Group 4(\[(?:[^][|]++|(?4))*])? ?repeats the group contents below at most once:
\[the literal [ (9110 / 1338 / 5B16)
Non-Capturing Group(?:[^][|]++|(?4))* *repeats the group contents below any number of times:
Negated Character Class[^][|]++ ++matches at least one character outside the set below:
]the literal ] (9310 / 1358 / 5D16)
[the literal [ (9110 / 1338 / 5B16)
|the literal | (12410 / 1748 / 7C16)
(?4)calls group 4 as a subroutine
]the literal ] (9310 / 1358 / 5D16)