Ok, the clips are to let you insert a roll film holder. If you press them in while holding the gg open you can see that they will provide you with extra space. I'm not sure about the knobs. But the ebony has them as well. Could they have something to do with the bellows?
Linhof's have some knobs like those that are used for rear movements. the knobs loosen/tighten against extendable metal posts to allow swing/tilt of the rear. Just a guess for this camera.