Description:

This is currently an experimental pragma to change Perl 5's standard
method resolution order from depth-first left-to-right (a.k.a -
pre-order) to the more sophisticated C3 method resolution order.

C3 is the name of an algorithm which aims to provide a sane method
resolution order under multiple inheritance. It was first introduced
in the Dylan language (see links in the manual SEE ALSO section), and
then later adopted as the preferred MRO (Method Resolution Order) for
the new-style classes in Python 2.3. Most recently it has been adopted
as the 'canonical' MRO for Perl 6 classes, and the default MRO for
Parrot objects as well.