Activate the Perl::Critic policy Variables::RequireInitializationForLocalVars
The policy Variables::RequireInitializationForLocalVars suggests to explicitly initialize local variables. This is because it is not really obvious that localized variables are initialized to undef per default. See https://metacpan.org/pod/Perl::Critic::Policy::Variables::RequireInitializationForLocalVars .
Tentatively running the policy against rel-11_0 showed violations in 44 files.