The Planar Reflection Caster component is the script that takes a reflection and assigns it to a material. It must always be attached to a Mesh Renderer component, and it will automatically track all of its materials and enable per-material settings to define whether the material uses the Reflection Color texture (_ReflectionTex), the Reflection Depth texture (_ReflectionDepth) and whether an additional Blur Pass should be used to blur the final output of the reflection. This blur pass should not be confused with the automatic blur applied through PBR shaders. Because of this, we recommend you disable the blur pass in most cases. It is provided as a form of backwards compatibility with shaders from previous versions.
The Reflection Fog pass can also be enabled from here, to simulate and closely match the fog present in the scene within the reflection itself.