Group 2(\+?\d{1,4}?[-.\s]?)? ?repeats the group contents below at most once:
\+?optionally matches the literal + (4310 / 538 / 2B16)
\d{1,4}?a digit, repeated between 1 and 4 times
?matches at most one character from the set below:
-the literal - (4510 / 558 / 2D16)
.the literal . (4610 / 568 / 2E16)
\sany whitespace character
?repeats the group contents below at most once:
\(the literal ( (4010 / 508 / 2816)
\d{1,4}?a digit, repeated between 1 and 4 times
\)the literal ) (4110 / 518 / 2916)
?matches at most one character from the set below:
-the literal - (4510 / 558 / 2D16)
.the literal . (4610 / 568 / 2E16)
\sany whitespace character
\d{1,4}a digit, repeated between 1 and 4 times
?matches at most one character from the set below:
-the literal - (4510 / 558 / 2D16)
.the literal . (4610 / 568 / 2E16)
\sany whitespace character
\d{1,4}a digit, repeated between 1 and 4 times
?matches at most one character from the set below:
-the literal - (4510 / 558 / 2D16)
.the literal . (4610 / 568 / 2E16)
\sany whitespace character
\d{1,9}a digit, repeated between 1 and 9 times