Slice and Splice challenge confusion

Tell us what’s happening:
I don’t get what, “The second array should remain the same after the function runs,” means, probably very obvious but for whatever reason it eludes me, can someone please explain it in different terms?

Your code so far


function frankenSplice(arr1, arr2, n) {
let x = arr1.slice(0,arr1.length)
arr2.splice(n,0,...x);
return arr2;
  }


  
 frankenSplice([1, 2, 3], [4, 5, 6], 1);

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Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-algorithm-scripting/slice-and-splice/

I believe that “second array” refers to the argument arr2