Examine source code of Panner for YouTube

{
  "name": "Panner for Youtube",
  "version": "1.2",
  "description": "Youtubeの音声を左右に振り分けるためのプラグインです",
  "manifest_version": 2,
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "panslider.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "permissions": [
    "https://www.youtube.com/*"
  ]
}