^start of line
.{4}any Unicode character (except for line terminators), repeated exactly 4 times
\$the literal $ (3610 / 448 / 2416)
.any Unicode character (except for line terminators)
\$the literal $ (3610 / 448 / 2416)
.+any Unicode 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