It is possible that much of the dark brown staining is grease that has accumulated from the stove, oven and broiler which has darkened with heat.
However, the device that is bundling the wires near the top definitely looks as if it has been degraded by heat. Also, if enough grease accumulates and it is overheated, the grease itself can become a fire hazard.
I would seriously consider cleaning up all the darkened areas to remove the grease, checking the wires to see if the seem brittle or charred in any way and possibly replacing the wiring bundle.
You also should check to make sure that there is no blockage of venting (or gaps in venting pipes/tubes) that is causing hot gasses to be misdirected to this area.