Examine source code of Whittle

{
  "manifest_version": 2,
  "name": "Whittle",
  "description": "Create a hide list of homes that you don't want to see in your searches anymore. Whittle them away!",
  "version": "0.4.2",
  "options_ui": {
    "page": "options.html",
    "chrome_style": true
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "compiled/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.zillow.com/*",
        "*://*.redfin.com/*",
        "*://*.trulia.com/*",
        "*://*.realtor.com/*"
      ],
      "js": [
        "compiled/content_script.js"
      ]
    },
    {
      "matches": [
        "*://*.zillow.com/*",
        "*://*.redfin.com/*",
        "*://*.trulia.com/*",
        "*://*.realtor.com/*"
      ],
      "run_at": "document_start",
      "js": [
        "compiled/apply.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "compiled/fetch.js",
    "whittle-logo.png"
  ]
}