Another one of those LED ring lights wound up in the Thing-O-Matic, affixed to the underside of the Z stage with double-sticky foam tape. You can see the whole ring reflected in that picture, but the front third of the ring obscured what the nozzle was doing.
So I sawed out one of the three-LED strings to open a gap:
Unfortunately, the designers arranged things so that the ballast resistor for each string sits directly above the last LED of the adjacent string. The white wire you can barely see connects the ballast resistor that drove the now-missing string on the left to the via feeding the first string on the right.
It now fits around the extruder with the gap exactly matching the opening in front of the Thermal Core.
Power comes from a screw terminal connector I hacked into the 4-pin block that used to be part of the 20+4-pin ATX power block at the Motherboard. There’s a length of overly stout 4-wire cable leading to a kludged not-a-connector made of square pins and heatshrink tubing jammed into the block.
It provides +12, +5, +3.3 V, and ground for the fan and LED lighting.
Most of the light in that last picture comes from LED strips on either side of the front opening. My Shop Assistant won a meter of warm-white LEDs at the 3rd Ward Make-a-Thon [Update: dead link. Try their pix from the event.] and graciously allowed me to chop off two 6-LED strips for a good cause.