Sometimes for me I find it more readable to place the inner reference in brackets, which sort of serves to remind me that it's a reference.

@{$self}{ qw( wins places shows losses ) } = ....
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We already know $self is a hashref. What happens when you put an @ in front of a hash, and a pair of curly brackets after it? Let's look at the similar syntax, but first remove the reference indirection (and complexity):

@somehash{ qw( wins places shows losses ) } = ....
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That should ring a bell (you're looking at a hash slice).