XXX.pm exports a function called XXX that you can put just about anywhere in
your Perl code to make it die with a YAML dump of the arguments to its right.

The charm of XXX-debugging is that it is easy to type, rarely requires parens
and stands out visually so that you remember to remove it.

XXX.pm also exports WWW, YYY and ZZZ which do similar debugging things.

WWW: https://metacpan.org/release/XXX