Module keyword as a datatype in C#?

I found some code on github in C#. It starts out in a way I’ve never seen before and I can’t find any info on it.

using System.Linq;
using UnityEngine;
using System.Collections.Generic;
 
public class ModularWorldGenerator : MonoBehaviour
{
public Module[] Modules;
public Module StartModule;

What is Module? Is it a datatype? I tried ctrl + ’ but found nothing. I looked at the C# keywords on the Microsoft site and found nothing.

Yes module is a class in this case, should be defined somewhere in the code you downloaded…if not you won’t be able to use it.