\ba Unicode word boundary
0?optionally matches the literal 0 (4810 / 608 / 3016)
\d{3}a Unicode decimal digit, repeated exactly 3 times
\sa Unicode whitespace character
\d{3}a Unicode decimal digit, repeated exactly 3 times
\sa Unicode whitespace character
\d{3}a Unicode decimal digit, repeated exactly 3 times
\ba Unicode word boundary
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