MRT on frame buffer + render texture

I was wondering if it is possible to do MRT on actual frame buffer and another render texture combination.

I have seen plenty of multiple rendertexture based examples but nothing that shows if it can be done with frame buffer.

I can probably do with multiple camera stacking, but I would really want to try MRT way because it should be simpler and faster.

Any one with good example?

AFAIK this isn’t possible even outside of Unity.