Determines the visual appearance of the inspector for all of its different themes.
Themes with the “Default” prefix refer to light themes that are the default in the free versions of Unity.
Themes with the “Pro” prefix refer to the dark themes that are the default in the paid versions of Unity.
Themes with the “Classic” suffix refer to the default theme in Unity versions older than 2019.3.
Themes with the “Modern” suffix refer to the default theme in Unity versions 2019.3 and afterwards. This is sometimes also called the “Flat” UI.