The aforementioned well-labeled board, complete with over a dozen test points and the essential control hardware.

Unlike the STMicroelectronics LED drivers we found in the Development Kit 2, this IC array hails from Texas Instruments:

3x Texas Instruments TLC59401 16-Channel LED Driver with Dot Correction and Grayscale PWM Control

On the reverse, we see a pair of (relatively) large capacitors—probably necessary to smooth the intermittent load of pulsing such a huge array of IR LEDs.