^start of line
\d{1,4}a digit, repeated between 1 and 4 times
\,the literal , (4410 / 548 / 2C16)
.?optionally matches any character (except for line terminators)
,the literal , (4410 / 548 / 2C16)
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