\sany whitespace character
transthe literal text trans (case insensitive) \s+any whitespace character, repeated at least once
\sany whitespace character
.*?any character (except for line terminators), repeated any number of times
\s+any whitespace character, repeated at least once
\sany whitespace character
endtransthe literal text endtrans (case insensitive) \sany whitespace character
x modifier: extended. Ignores unescaped whitespace and comments outside character classes
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