in src/pages/BasicWebView.ts [114:137]
  protected async receiveMessage(message: { [key: string]: any }): Promise<void> {
    if (!this.panel) {
      return;
    }
    switch (message.command) {
      case 'documentReady':
        await this.postMessage({
          command: 'showOnStartup',
          value: this.context.globalState.get(this.config.showOnStartup),
        });
        break;
      case 'toggleShowPage':
        this.context.globalState.update(this.config.showOnStartup, message.value);
        break;
      case 'executeCommand':
      case 'openLink':
        Telemetry.sendEvent(Constants.telemetryEvents.webPages.action, message);
        break;
      case 'notification':
        showNotification(message.value);
        break;
    }
  }