Examine source code of SLNT.stream

{
  "manifest_version": 2,
  "name": "SLNT.stream",
  "description": "Use the SLNT.stream extension to listen to music with your favourite streamer",
  "version": "2.0.2",
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitch.tv/*",
        "*://*.youtube.com/*"
      ],
      "js": [
        "js/twitch.js",
        "js/youtube.js",
        "js/communication.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "/assets/*"
  ],
  "browser_action": {
    "default_icon": {
      "16": "/assets/img/icon16.png",
      "48": "/assets/img/icon48.png",
      "128": "/assets/img/icon128.png"
    }
  },
  "icons": {
    "16": "/assets/img/icon16.png",
    "48": "/assets/img/icon48.png",
    "128": "/assets/img/icon128.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "slntFF@slnt.stream"
    }
  }
}