^start of line
.*any Unicode character (except for line terminators), repeated any number of times
itemthe literal text item (case sensitive) .*any Unicode character (except for line terminators), repeated any number of times
\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match
\ba Unicode word boundary
polthe literal text pol (case sensitive) .+?any Unicode character (except for line terminators), repeated at least once
\ba Unicode word boundary
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
u modifier: unicode. Treats the pattern and subject as UTF-16