The round object is the black wire wrapped around the bundle for a few feet to pull the rest of the bundle. That way you only connect one wire to the pull string and give flexibility for making turns when pulling wire into that CONCRETE PULL BOX. It is not an electronics enclosure as the the bottom is fully open and mounted directly on top of the dirt. You don't do that with electronics because of moisture.
There are no separate signal wires, all the same gauge and suitable for 120/240 VAC.
The discoloration on one white wire could be explained by dirt.
The real question for me is why are there 50 posts about this?