So, we have a remove-before-flight bucket designed to catch some sort of fluid which might overflow during roll-to-pad? That makes sense. As for Kourou, perhaps the fluid in question isn't added when they roll out. They have a tower for vertical payload mate in Kourou, so maybe they add whatever it is after going vertical - so no need to catch slop during roll?

I suppose another option is something needed for the cold of Russia or Kazakhstan vs. the heat of the jungle. Any photos of a roll-out in Russia or Kazakhstan without buckets? And if so, was it summer or winter?