Negative Lookbehind(?<!\S) \Sany character that is not Unicode whitespace
\d+a Unicode decimal digit, repeated at least once
Non-Capturing Group(?:,\d+)? ?repeats the group contents below at most once:
,the literal , (4410 / 548 / 2C16)
\d+a Unicode decimal digit, repeated at least once
?optionally matches the literal (3210 / 408 / 2016)
xthe literal x (12010 / 1708 / 7816) (case sensitive)
?optionally matches the literal (3210 / 408 / 2016)
\d+a Unicode decimal digit, repeated at least once
Non-Capturing Group(?:,\d+)? ?repeats the group contents below at most once:
,the literal , (4410 / 548 / 2C16)
\d+a Unicode decimal digit, repeated at least once
Non-Capturing Group(?: ?x ?\d+(?:,\d+)?)* *repeats the group contents below any number of times:
?optionally matches the literal (3210 / 408 / 2016)
xthe literal x (12010 / 1708 / 7816) (case sensitive)
?optionally matches the literal (3210 / 408 / 2016)
\d+a Unicode decimal digit, repeated at least once
Non-Capturing Group(?:,\d+)? ?repeats the group contents below at most once:
,the literal , (4410 / 548 / 2C16)
\d+a Unicode decimal digit, repeated at least once
g modifier: global. Finds all matches instead of stopping after the first