The screw ? I imagine the plastic pillar/ boss that the original screw went into has failed (split.snapped) and the replacement simply goes right thrrough into the wall behind, and the washer covers the damaged plastic.
May need some care re-fitting not to snag the internal wiring, which I bet without seeing it, combines the best of spaghetti and violin strings.
I'm curious as to how they got the downstairs ring, the upstairs ring, the water heater and the security alarm (burglar alarm?) all on one CB. (Not to mention why it doesn't keep tripping)
"How and why?" indicates a misunderstanding of the ingenuity of complete and utter idiots. Sparking Chip I`m sure you`ve witnessed as many idiots as I have and therefore your question is rhetorical