The TilePaletteToolbar() throws an Error in the Console when trying to use it

To reproduce:

1. Download the "My Project (92).zip" and open it in Unity
2. Inspect the Console window

Expected result: The Console window is empty - No Errors or Warnings are present
Actual result: In the Console window you can see an Error:

"Assets/Editor/MyTilePaletteOverlay.cs(14,20): error CS0246: The type or namespace name 'TilePaletteToolbar' could not be found (are you missing a using directive or an assembly reference?)"

Reproducible in Unity 2022.2.0b5, and 2023.1.0a4