>perl -MYAPE::Regex::Explain -E 'say YAPE::Regex::Explain->new(q<[\s+,:]>)->explain'
The regular expression:

(?-imsx:[\s+,:])

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  [\s+,:]                  any character of: whitespace (\n, \r, \t,
                           \f, and " "), '+', ',', ':'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------