Examine source code of A2OJ Reimagined

{
  "manifest_version": 2,
  "name": "A2OJ Reimagined",
  "version": "2.4",
  "description": "Improves experience of a2oj.",
  "icons": {
    "128": "icons/icon-1.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.a2oj.com/*"
      ],
      "js": [
        "js/enhance.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/icon-1.png",
    "default_title": "A2OJ Reimagined"
  },
  "permissions": [
    "*://codeforces.com/*",
    "storage"
  ]
}