Examine source code of CrossTracker

{
  "icons": {
    "16": "icon16.plasmo.e7bcd3ac.png",
    "32": "icon32.plasmo.ce39377b.png",
    "48": "icon48.plasmo.3c17e113.png",
    "64": "icon64.plasmo.df317abe.png",
    "128": "icon128.plasmo.6a4310c5.png"
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "icon16.plasmo.e7bcd3ac.png",
      "32": "icon32.plasmo.ce39377b.png",
      "48": "icon48.plasmo.3c17e113.png",
      "64": "icon64.plasmo.df317abe.png",
      "128": "icon128.plasmo.6a4310c5.png"
    }
  },
  "version": "1.3.1",
  "author": "CrossTracker",
  "name": "CrossTracker",
  "description": "",
  "background": {
    "scripts": [
      "static/background/index.js"
    ]
  },
  "permissions": [
    "scripting",
    "*://*.twitch.tv/*"
  ],
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c8422a08-c8e2-4f12-bd83-7a2a620c0eee}"
    }
  }
}