^start of line
Negative Lookahead(?!\+33) \+the literal + (4310 / 538 / 2B16)
\+the literal + (4310 / 538 / 2B16)
\d{1,3}a digit, repeated between 1 and 3 times
\d{4,9}a digit, repeated between 4 and 9 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