(?im)applies the following effective flags to the remainder of the pattern: gim i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
^start of line
\"?optionally matches the literal " (3410 / 428 / 2216)
\w+any word character, repeated at least once
Non-Capturing Group(?:[\W&&[^@]]?) Character Class[\W&&[^@]]? ?matches at most one character from the resulting set below:
\Wany non-word character
&&keep only members also present in the set below contains all characters except those below:
@the literal @ (6410 / 1008 / 4016)
\w+any word character, repeated at least once
\k<c1>the text saved by group c1
@the literal @ (6410 / 1008 / 4016)
Non-Capturing Group(?:\[?(?:\d{3}\.?){0,4}\]?|(?:[\w&&[^\d]]+[\.\-]?)*(?<=\.\w{2,6})) 1st Alternative\[?(?:\d{3}\.?){0,4}\]? \[?optionally matches the literal [ (9110 / 1338 / 5B16)
Non-Capturing Group(?:\d{3}\.?){0,4} {0,4}repeats the group contents below between 0 and 4 times:
\d{3}a digit, repeated exactly 3 times
\.?optionally matches the literal . (4610 / 568 / 2E16)
\]?optionally matches the literal ] (9310 / 1358 / 5D16)
2nd Alternative(?:[\w&&[^\d]]+[\.\-]?)*(?<=\.\w{2,6}) Non-Capturing Group(?:[\w&&[^\d]]+[\.\-]?)* *repeats the group contents below any number of times:
Character Class[\w&&[^\d]]+ +matches at least one character from the resulting set below:
\wany word character
&&keep only members also present in the set below contains all characters except those below:
\da digit
?matches at most one character from the set below:
\.the literal . (4610 / 568 / 2E16)
\-the literal - (4510 / 558 / 2D16)
Positive Lookbehind(?<=\.\w{2,6}) \.the literal . (4610 / 568 / 2E16)
\w{2,6}any word character, repeated between 2 and 6 times
$end of line
g modifier: global. Finds all matches instead of stopping after the first