LED Light Add On  

RE: LED Light Add On

Not as far as I know. But there are several light addons on Printables. You have to source some LED strips yourself. This has the advantage that you have a choice of several designs and this is also cheaper than the one fixed design that Prusa offers for their Original Enclosure. I have that one but found it totally unflexible as it has just two settings, on and off. They promised a so called "Smart Box" in the beginning together with the enclosure that would offer "many options", but this project got lost on the way to newer and shinier things, I guess.

I included an LED strip along the side and front over the printer in the enclosure and can control the strip via a GPIO plugin in OctoPrint. It is not expensive to do this and you can do all kinds of light effects with the LEDs, like heating status, failure status, printing status etc.

RE:

I've used this one (or rather, the Mk3 version of it) at one point, and it worked great:

https://www.printables.com/model/493459-led-light-bar-prusa-mk4

Doesn't plug into the board though but I don't see why that's necessary. I just ran it to a smartplug that turned the printer and the LED lights on at the same time.

When I moved my printers into enclosures, I designed my own LED system.

RE:

They promised a so called "Smart Box" in the beginning together with the enclosure that would offer "many options", but this project got lost on the way to newer and shinier things, I guess.

I wonder if the expansion board in the C1 is where that development was diverted. Once that board shows up in the store as a replacement part for the C1, I can see people wanting to use it for MK4 (not sure if it would work on MK3 and earlier, but it might because it plugs into the MMU connector) in an enclosure. Would probably need some reorganizing of the firmware to pull the C1 enclosure features into a MK4 firmware build. I haven't looked at the firmware code, but hopefully it would be as simple as an adjustment to the makefile...