It is the star operator * which is used in line 1 to pack into a list a variable number of arguments.
On other lines it is used to unpack them
https://docs.python.org/3/reference/expressions.html#expression-lists

The same goes to pack keyword arguments into a dict with ** operator
https://docs.python.org/3/reference/expressions.html#dictionary-displays

For a number of 2 or more digits, the last 2 digits determine whether it is divisible by 4.

([02468][048]|[13579][26]) matches all combinations of the last 2 digits that would make the number divisible by 4.

Don't post solution in discourse next time (It's visible in dashboard), thanks ~~ :)