I really meant to use reverse. According to Perl::Critic::Policy::BuiltinFunctions::ProhibitReverseSortBlock

Conway says that it is much clearer to use reverse than to flip $a and $b around in a sort block. He also suggests that, in newer perls, reverse is specifically looked for and optimized, and in the case of a simple reversed string sort, using reverse with a sort with no block is faster even in old perls.