Examine source code of Porn Out!

{
  "manifest_version": 2,
  "name": "Porn Out",
  "version": "1.0",
  "description": "Blocking porn & adult materials",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icon48.png"
  },
  "background": {
    "scripts": [
      "event.js"
    ],
    "persistent": true
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "storage",
    "tabs"
  ]
}