Lee/BuiltIn/Lit is an open-source, high-performance PBR shader for Unity’s Built-in Render Pipeline. It supports mobile platforms with efficient implementation and a limited number of shader variants for easy deployment and maintenance. Features include customizable shader GUI (CustomEditor), material baking (GI/Lightmap), metallic, roughness, normal, emission, and occlusion support. The content is highly customizable, suitable for various project types and genres without restrictions.