Group 1([A-Z]{3} *\d{1,2}) {3}matches exactly 3 characters from the set below:
A-Zone character from A (6510) to Z (9010) (case insensitive)
*the literal (3210 / 408 / 2016) , repeated any number of times
\d{1,2}a digit, repeated between 1 and 2 times
*the literal (3210 / 408 / 2016) , repeated any number of times
-the literal - (4510 / 558 / 2D16)
*the literal (3210 / 408 / 2016) , repeated any number of times
(?1)calls group 1 as a subroutine
g modifier: global. Finds all matches instead of stopping after the first
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters