^start of string
Group filename(?P<filename>.+\.cs) .+any character (except for line terminators), repeated at least once
\.the literal . (4610 / 568 / 2E16)
csthe literal text cs (case insensitive) \(the literal ( (4010 / 508 / 2816)
\d+a digit, repeated at least once
\d+a digit, repeated at least once
\)the literal ) (4110 / 518 / 2916)
:the literal : (5810 / 728 / 3A16)
\040the literal (408 / 3210 / 2016)
Group level(?P<level>\w+) \w+any word character, repeated at least once
\040the literal (408 / 3210 / 2016)
.+any character (except for line terminators), repeated at least once
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters
g modifier: global. Finds all matches instead of stopping after the first
x modifier: extended. Ignores unescaped whitespace and comments outside character classes