^start of line
.*any character (except for line terminators), repeated any number of times
Dthe literal D (6810 / 1048 / 4416) (case insensitive)
.*any character (except for line terminators), repeated any number of times
$end of line
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
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters