Perl really doesn’t have the notion of “[passing parameters by] reference.”

That's not true. In fact, Perl always passes parameters by reference.

$ perl -E'sub { $_[0] = "abc" }->($x); say $x'
abc
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I think you wanted to point out the phrase "passing by reference" has been incorrectly used instead of "passing a reference" throughout this thread, but you took a wrong turn somewhere.