Flutter MaterialApp里的title到底是什么？

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      title: '多任务管理器titer',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomePage(),
    ),
  );
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("本界面数据titer"),
      ),
    );
  }
}