The seven segment displays and the encoders are attached to the matrix board with silicone sealent. This makes it easier to replace one if required which would be more difficult if Super Glue or epoxy were used.
The controls on the left of the panel are for the transponder, the seven segment displays show the squawk code input by the rotary encoders. The controls on the right are for the TCAS system.
The first lighting check
Another rat's nest!
The completed panel. It never ceases to amaze me how much wire ends up coming from even a small panel like this.