The add-on cannot be uninstalled.

If you are having trouble deleting or reinstalling the add-on, please try the following steps:

1. Open the Pencil+ 4 Line add-on folder.
   Open [Add-ons] in the [Preferences] menu. Display the information for Pencil+ 4 Line to find the folder where the add-on is installed.
   You can also click on the directory line to open the folder where the add-on is installed.
   
2. Terminate all Blender processes.
3. Delete all the items in the Pencil+ 4 Line add-on folder.