An Interesting Discolored Ffarquhar Station

I have a Ffarquhar where the base at least had yellowed, it came in a boxed set from Japan so unless it was played with a lot I suppose it was from heat, which I have heard can also cause the flame retardant Bromine used in some plastic to yellow (Famously, the Super Nintendo allegedly warmed itself up so much when running that the early consoles with a poor Bromine mix would turn themselves yellow, no light required).
Could be a mix of that and light, interesting how the platform inside the station is less yellowed like it was kept with the top on and it was getting exposure through the door and window slits.