Examine source code of Media Mist

{
  "manifest_version": 2,
  "name": "MediaMist",
  "description": "Block any ads on youtube.",
  "version": "1.4.8",
  "icons": {
    "32": "icons/icon-32.png",
    "64": "icons/icon-64.png",
    "256": "icons/icon-256.png",
    "512": "icons/icon-512.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "http://*/*",
    "https://*/*",
    "storage",
    "notifications",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "64": "icons/icon-64.png"
    },
    "default_popup": "browserAction/index.html",
    "default_title": "Media Mist"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{da61d2e7-6a5a-4587-bbaa-a771aba3ba7c}"
    }
  }
}