I have opened the hatch_hood.jbeam to study the code, I see slotType in the code, what is exactly is a slotType and what does it do for the game?
Defines which part slot it fits in. Take for example any engine part for the pickup, has slottype pickup_engine. Somewhere in the pickup jbeam there is a line which defines that the pickup has the pickup_engine slot for the engines to go into from the parts selector.