Unity editor extension? What is PropertyDrawer? Custom script variable plotting?

1. What is PropertyDrawer?

原话：Base class to derive custom property drawers from. Use this to create custom drawers for your own Serializable classes or for script variables with custom PropertyAttributes.

Plain language: You can customize the style of your own instantiable classes or structures or variables in custom feature classes.

2. Final effect?

from this

to this

3. How to achieve it?

https://www.bilibili.com/video/BV1Nd4y1o7WN