^start of line
3the literal 3 (5110 / 638 / 3316)
Negative Lookahead(?!30|40) \d{2}a digit, repeated exactly 2 times
\.the literal . (4610 / 568 / 2E16)
\d{3}a digit, repeated exactly 3 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