This page describes the behavior of a Light component when you set its Mode property to Mixed. These are also known as Mixed Lights.
Mixed Lights combine elements of both realtime and baked lighting. You can use Mixed Lights to combine dynamic shadows with baked lighting from the same light source, or when you want a light to contribute direct realtime lighting and baked indirect lighting.
Note that if you disable Baked Global Illumination in your Scene, Unity forces Mixed Lights to behave as though you set their Mode to Realtime. When this happens, Unity displays a warning on the Light component Inspector.