This is the LED backlight's controller. The backlight seems to run on a fairly high voltage and the backlight cable is thus quite thin (right angle cable in the first image.) It is covered by plastic cover.

The controller appears to be built using a bunch of MOSFETs and inductors as a boost/buck/current limiting DC-DC converter. The board is well-cooled with a lot of heavy copper fill areas, in my experience it does not need extra cooling to be okay

Straight ribbon cable goes to TCON to allow backlight contrast dynamic dimming and control on/off/brightness.