Upon opening a mini app, World App will set a window.WorldApp object. This object contains useful metadata about the device, user, and commands that can be used to customize the mini app. 
{
  "pending_notifications": "number",
  "supported_commands": [
    {
      "name": "string",
      "supported_versions": ["number"]
    }
  ],
  "world_app_version": "number",
  "safe_area_insets": {
    "top": "number",
    "right": "number",
    "bottom": "number",
    "left": "number"
  },
  "device_os": "string",
  "is_optional_analytics": "boolean"
}
For simplicity we make it easy to access these values in Minikit. 
interface MiniKit {
  deviceProperties: {
    safeAreaInsets: { // The safe area insets of the device.
      top: number;
      right: number;
      bottom: number;
      left: number;
    };
    deviceOS: string;
    worldAppVersion: number; // 
  };
  user: {
    optedIntoOptionalAnalytics: boolean; // If this is false, you should not collect any analytics for this user.
  };
}