Examine source code of Casino Blocker

{
  "manifest_version": 2,
  "name": "Casino Blocker",
  "version": "1.0.6646",
  "author": "Jeroen Swen",
  "description": "Blocks gambling (related) websites and displays an awareness notification.",
  "icons": {
    "512": "icons/icon-512.png"
  },
  "background": {
    "scripts": [
      "js/main.js"
    ]
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "notifications",
    "<all_urls>"
  ]
}