\ba Unicode word boundary
\d+a Unicode decimal digit, repeated at least once
Uthe literal U (8510 / 1258 / 5516) (case sensitive)
N?optionally matches the literal N (7810 / 1168 / 4E16) (case sensitive)
\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