%hash = EXPR;
[download]

does something like

my @anon = LIST;
%hash = ();
while (@anon) {
   my $k = shift(@anon);
   my $v = shift(@anon);
   $hash{$k} = $v;
}
[download]

So if you have two values for the same key, the latter prevails.

(There's no actual @anon created; the stack is used.)