Examine source code of holypics

{
  "manifest_version": 2,
  "name": "holypics",
  "version": "1.0",
  "description": "Hide all pornographic pictures on any page",
  "homepage_url": "https://github.com/karamokoisrael/parental_spying",
  "permissions": [
    "<all_urls>",
    "activeTab",
    "tabs",
    "cookies",
    "storage"
  ],
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon.png"
  },
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_title": "holypics",
    "default_popup": "popup/main.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "main.js"
      ],
      "css": [
        "main.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}