(?im)applies the following effective flags to the remainder of the pattern: gmi 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
.+any character (except for line terminators), repeated at least once
\s*any whitespace character, repeated any number of times
\+the literal + (4310 / 538 / 2B16)
\s*any whitespace character, repeated any number of times
.+any character (except for line terminators), repeated at least once
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string