Examine source code of Discord RPC Pack

{
  "manifest_version": 2,
  "name": "Discord RPC Pack",
  "version": "0.0.7",
  "description": "This is an expansion pack for the extension Discord Rich Presence. It adds discord RPC support for Soundcloud, youtube and twitch.",
  "background": {
    "scripts": [
      "extensionId.js",
      "background.js",
      "Twitch/background.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png",
    "512": "icons/icon512.png"
  },
  "content_scripts": [
    {
      "js": [
        "extensionId.js",
        "Soundcloud/main.js"
      ],
      "matches": [
        "https://soundcloud.com/*"
      ]
    },
    {
      "js": [
        "extensionId.js",
        "YouTube/main.js"
      ],
      "matches": [
        "https://www.youtube.com/*"
      ]
    },
    {
      "js": [
        "extensionId.js",
        "YouTubeMusic/main.js"
      ],
      "matches": [
        "https://music.youtube.com/*"
      ]
    },
    {
      "js": [
        "extensionId.js",
        "Twitch/main.js"
      ],
      "matches": [
        "https://www.twitch.tv/*"
      ]
    }
  ]
}