I agree that it tends to be design smell to need it but sometimes it's just the most natural way to solve a problem. I've done it three times, I think, and ended up taking one back when I realized my design error. This is the current best way to do it: Catalyst::Component::ApplicationAttribute.

# Moose extends etc
with "Catalyst::Component::ApplicationAttribute";

sub somesub {
    my $self = shift;
    my $ctx = $self->_application;
}
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It handled handles the weakening properly and with the leading underscore emphasizes the private/dangerous nature of its usage.