Make stuff not public if it doesn't need to be

Assets/Scripts/GameMusicHandler.cs

@@ -3,7 +3,7 @@ using UnityEngine;
 [RequireComponent(typeof(AudioSource))]
 public class GameMusicHandler : MonoBehaviour
 {
-    public AudioClip[] audioClips;
+    [SerializeField] private AudioClip[] audioClips;
     private AudioSource audioSource;
     private int lastIndex = -1;
     private int currentIndex = 0;