\s*any whitespace character, repeated any number of times
-?optionally matches the literal - (4510 / 558 / 2D16)
\d+a digit, repeated at least once
?repeats the group contents below at most once:
\.the literal . (4610 / 568 / 2E16)
\d+a digit, repeated at least once
Non-Capturing Group(?:[eE][+-]?\d+)? ?repeats the group contents below at most once:
ethe literal e (10110 / 1458 / 6516) (case sensitive)
Ethe literal E (6910 / 1058 / 4516) (case sensitive)
?matches at most one character from the set below:
+the literal + (4310 / 538 / 2B16)
-the literal - (4510 / 558 / 2D16)
\d+a digit, repeated at least once
\s*any whitespace character, repeated any number of times