two things i've noticed since building my first filler on this branch.
the connection point for incoming gas lines is offset from the new image (which is beautiful)
also the animation is out of sync.. i guess?
it shows a canister of gas appearing inside and then visually dropping onto the ground in front of it.
the building then goes back to the 'blank' state and the canister vanishes, eventually a dupe wanders up and pulls the canister out of the air.
perhaps the last part of the animation is intended for when the dupe comes up to it??
edit: also when stopped the tool tip and mouse over information gives no clue as to what is going on, it appears broken if you don't know already
ie: gee, what gas do i need to program my emptier for??
build a canister filler, connect it to a source of gas and observe..