^start of string
\+?optionally matches the literal + (4310 / 538 / 2B16)
-?optionally matches the literal - (4510 / 558 / 2D16)
0*the literal 0 (4810 / 608 / 3016) , repeated any number of times
Group 2([[:digit:]]+,[[:digit:]]+?) Character Class[[:digit:]]+ +matches at least one character from the set below:
[:digit:]a digit [0-9]
,the literal , (4410 / 548 / 2C16)
Character Class[[:digit:]]+? +?matches at least one character from the set below:
[:digit:]a digit [0-9]
0*the literal 0 (4810 / 608 / 3016) , repeated any number of times
$end of string, or before its final line terminator
g modifier: global. Finds all matches instead of stopping after the first