Examine source code of Airbnb Total

{
  "name": "Airbnb Total",
  "version": "1.4resigned1",
  "manifest_version": 2,
  "description": "Total price for days on airbnb.",
  "permissions": [
    "tabs",
    "webRequest",
    "*://*.airbnb.com/*"
  ],
  "browser_action": {
    "default_icon": "social-media-128.png"
  },
  "applications": {
    "gecko": {
      "id": "aleodortabarcea@gmail.com"
    }
  },
  "background": {
    "scripts": [
      "attacher.js"
    ]
  },
  "icons": {
    "16": "social-media-16.png",
    "48": "social-media-48.png",
    "128": "social-media-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.airbnb.com/s/*"
      ],
      "js": [
        "airbnb_total.js"
      ]
    }
  ]
}