<This is one idiom,

<%hash = (%hash, e => 'f', g => 'h', i => 'j');
<%hash = (%otherhash, %hash);
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This code reminds me of writing the comma operator in this way: ",=", so to concatenate a hash:

my %hash1 =qw/ One 1 Two 2 Three 3/;
my %hash2 =qw/ Four 4 Five 5 Six 6/;

%hash1 ,= %hash2;

say keys %hash1;
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