Reverse Engineer
Reverse Engineers have a knack for figuring out how stuff works. After seeing a piece of machinery function, you can deduce how it functions. You have advantage on Intelligence (Investigation) checks in the following situations outside of combat:
Determining how to repair or disable a specific vehicle, siege weapon, or other large simple machine you observed in operation.
Determining how to reset or disarm a specific trap you observed triggering.
After a length of time determined by your DM, learning how to recreate a complex machine you successfully disassembled.