Examine source code of CF ON STEROIDS

{
  "name": "CF ON STEROIDS",
  "description": "It enhances the Codeforces user profile according to selected options locally",
  "version": "1.0.0",
  "browser_action": {
    "default_popup": "popup/steroids.html",
    "default_icon": "assets/ico64.png"
  },
  "icons": {
    "16": "assets/ico16.png",
    "48": "assets/ico48.png",
    "64": "assets/ico64.png",
    "128": "assets/ico128.png",
    "256": "assets/ico256.png",
    "512": "assets/ico512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://codeforces.com/*",
        "https://codeforces.com/*"
      ],
      "js": [
        "script.js"
      ],
      "all_frames": true
    }
  ],
  "permissions": [
    "tabs",
    "storage"
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+F",
        "mac": "MacCtrl+Shift+F"
      },
      "description": "Opens steroids.html"
    }
  },
  "manifest_version": 2
}