Examine source code of Topic validation

{
  "browser_action": {
    "default_icon": "rocket.png",
    "default_popup": "validation.html"
  },
  "commands": {
    "_execute_browser_action": {
      "description": "Validate topic on Stepik",
      "suggested_key": {
        "default": "Ctrl+Shift+V",
        "mac": "MacCtrl+Shift+V"
      }
    }
  },
  "description": "Helper for hyperskill topics creation",
  "manifest_version": 2,
  "name": "Topic validation",
  "permissions": [
    "*://stepik.org/*",
    "*://cogniterra.org/*",
    "*://hyperskill.org/*",
    "activeTab",
    "storage"
  ],
  "version": "0.4",
  "browser_specific_settings": {
    "gecko": {
      "id": "{0f5efe2c-6097-4176-ad48-a77c4c71b9d4}"
    }
  }
}