What is this, and can I remove it without draining coolant?

You can remove it. No coolant there.
It provides a high idle speed until coolant heats up. I disabled mine. Do not like high rpm when engine is cold.

 

I disconnected the bimetallic coil inside the housing.

 

I've actually just removed mine, cleaned it up and I am about to reinstall it.
I need to work out how to set it up so that it drops back to neutral adjustment when the car gets up to temperature. The first part of the curved edge is marked with a couple of lines and 20 degrees, so that will be my first reference point.

Looking at it, the adjustment screw on the arm should allow you to adjust how much throttle it maintains until it warms up. i.e. if adjusted correctly the engine won't be 'racing'.
I don't believe mine had been disabled or totally neutralised. I can see the benefit of it being in place.

 

It is part of the emissions control equipment.

 

Yes it is part of the emissions control equipment as it causes the engine to idle faster when cold thereby warming up faster and not dying because its dead cold and getting a rich mixture spike. Having said that a typical Calif smog test is done with the engine as hot as possible so the fast idle cam is a non starter and difficult for a smog tech to check due to its location. Ferrari actually has a way of setting it by degrees of rotation but I have never used it. I have mine adjusted via the speed screw to idle at about 1K when first started cold. Once it smooths out, about 5 seconds, it is completely drivable and doesn't die at idle It does get to about 1200 before it gets hot enough to rotate the cam all the way at which point the idle speed screw is not touching the cam. On mine, a 78 GTS NA, with Pertronix ignition it is difficult to keep the engine running while slowly backing it out of the garage, getting out of the car and opening the gate and so on without the high speed idle cam. I insist it run and drive like a "normal" car that my wife could drive in a pinch and without the high speed idle cam that would never happen. FYI I generally do not use the mixture enrichment mechanism unless I leave it parked outside in a really cold environment like freezing.

It works great for me.

Barry