The goal of this tool is to have more control on the Constraints of Cloth Component.
Were you trying to make hair move with cloth but you couldn't select the constraints you need? Were you trying to make a T-Shirt having different motion constraints depending on the area of the shirt?
I am sure you had the same problem I've been having and couldn't as unity doesn't have detailed selection tools. With this tool you don't even need detailed selection tools.
Just make an image similar to your UV map to indicate constraints and that's it!
WARNING:
Doesn't work on Unity 2019. Should work fine with other versions.