Examine source code of Virtual Keyboard Basic

{
  "manifest_version": 2,
  "name": "Virtual Keyboard Basic",
  "version": "1.0",
  "description": "A virtual keyboard is a user interface component that allows users to input text by clicking on the keys displayed on the screen",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/key-logo.png"
    }
  },
  "icons": {
    "128": "images/key-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{65f66fc2-497a-4870-b42a-ed1f9ac98927}"
    }
  }
}