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Thus node is only available in a node editor context where raytracing is available. It will check the current (incoming) ray for specific properties and return true if they match.
The incoming ray is the ray evaluating the current surface spot.
This control is only available if the Boolean input is connected. If turned on, it will simply pass through the Boolean input to the output, completely bypassing the node.
These two columns are ray properties to check for. The first column depends on the type of ray, the second column covers additional properties.
The types of ray are mutually exclusive. A ray can only be on of these type, but not a combination of them:
The additional properties may be combined. For example, a ray may be a Pre-Process ray that is also a Camera ray.
This just inverts the result of the check from true to false and vice versa.
This control is only available if the Boolean input is connected. It will cause the value of the Boolean input to be combined with the result of the ray type check using Boolean Logic as explained here.