安装本地包
The Package Manager can load a package from anywhere on your computer even if you saved it outside your Unity Project folder (for example, if you have a package called com.unity.my-local-package and you save it on the Desktop but your Unity Project is under the Documents folder).
You can also use a folder inside your Project folder, provided that it is not one of the reserved Project sub-folders.
要从本地磁盘加载包，请执行以下操作：
1.在状态栏中单击添加 
按钮。
2.此时将显示用于添加包的选项。
3.从添加菜单中选择 Add package from disk 以显示文件浏览器。
4.导航到本地包的根文件夹。
5.在文件浏览器中双击 package.json 文件。
文件浏览器将关闭，然后包现在显示在包列表中，并带有 local 标签。
Local packages inside your Project
You can place a local package anywhere inside your Project except under these folders:
| 项目文件夹： | 原因： |
|---|---|
Assets |
If you place a package inside this folder, the Asset Database imports any Assets under this folder twice: once as Assets and once as Package contents. |
Library |
请勿修改此文件夹的内容。 |
ProjectSettings |
This folder is for settings Assets only. |
Packages |
If you place a package under this folder, the Package Manager automatically interprets it as an Embedded package, regardless of the reference in the Project manifest. |