The x as used here is the string multiplier, e.g.

$ perl -E 'say q{abc} x 3;'
abcabcabc
$
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It can also be used as a list multiplier, e.g.

$ perl -E '
> @arr = ( 0 ) x 5;
> $arr[ 3 ] = 7;
> say qq{Element $_: $arr[ $_ ]} for 0 .. $#arr;'
Element 0: 0
Element 1: 0
Element 2: 0
Element 3: 7
Element 4: 0
$
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I hope this is helpful.

Update: Expanded the second code example to make it clearer that an array has been initialised.