\_the literal _ (9510 / 1378 / 5F16)
Negative Lookahead(?!.*\bby\b) .*any character (except for line terminators), repeated any number of times
\ban ASCII word boundary
bythe literal text by (case insensitive) \ban ASCII word boundary
.*?any character (except for line terminators), repeated any number of times
$end of string, or before its final line terminator
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters