perl -MYAPE::Regex::Explain -e 'print YAPE::Regex::Explain->new(qr/^[\w.-]+\@myinfo.com/)->explain'
The regular expression:

(?-imsx:^[\w.-]+\@myinfo.com)

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):
----------------------------------------------------------------------
  ^                        the beginning of the string
----------------------------------------------------------------------
  [\w.-]+                  any character of: word characters (a-z, A-
                           Z, 0-9, _), '.', '-' (1 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  \@                       '@'
----------------------------------------------------------------------
  myinfo                   'myinfo'
----------------------------------------------------------------------
  .                        any character except \n
----------------------------------------------------------------------
  com                      'com'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------