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In the manual, one is shown under channels. How can you achieve it though?

Not sure why you would ever just cook a render to get only the reflections pass. Is there no way to get this pass plus the reflections+diffuse? I guess I don't understand why we can't get access to more channel types like reflections, diffuse, GI, etc. these are all essential to my post process workflow.

The Maxwell manual even says, "Rendering separately the diffuse and reflective components allows for greater flexibility when compositing." Yeah, it does, but I am not going to cook a render twice to get the reflections channel! This is a no-brainer, we need to be able to access this channel along with the others from a single render.

I agree that it would be great to get the reflections pass in one cook as a separate channel. When I composite the exteriors in after rendering, I often have mirrors and reflective surfaces reflecting the environment behind the camera which does not allow for me to use the Alpha since there is no transparency, so the reflections pass is a must simply to see and select the reflections that are supposed to be showing environment.

It may sound straightforward, if you're used to a biased renderer which splits up "light" into spec, diffuse and does so also for the material system. In Maxwell, just as in the real world, all light is really light that's reflected from a surface. The way it's reflected, in a diffuse or specular way is what gives you your reflections in the sense you are used to with other renderers. It's not so easy when you realize - when should one distinguish a specular reflection from a diffuse one? You usually don't have only lambert or roughness 0 materials. How much should a roughness 25 material contribute to the reflection channel? Currently we try to do a graduated change but the fact remains this can't be done in a single pass, or it can on the surface, but internally it's like running two simultaneous renders.

Thanks for the insight, Mihai. Is there a way to use network rendering to render both passes simultaneously using a single license?