The TransformOriginY property in the BaseStyles class represents the transform-origin-y CSS property. This property specifies the y-coordinate of the origin for transformations applied to an element. It is a nullable property of type Sandbox.UI.Length, allowing you to define the origin point in various units such as pixels, percentages, etc.

To use the TransformOriginY property, you can set it to a specific length value to define where the y-origin of the transformation should be. This can be useful when you want to control the pivot point for transformations like rotation or scaling.