- A machine part. It might be simply metallic or non-metallic and it may have some sorts of nondescript chips, crystals, wires, circuit boards, etc. No markings, serial numbers or exact idea of what it would do. The engineer has a feeling it is 'important' but he can't say why. He's just worried that if it gets thrown out, it'll come back to haunt the crew. (It was part of the life support system that was originally in the ship that broke down regularly in places like 'mid-jump' and 'in barren systems' so it WAS very critical, but that whole system got torn out 4 years ago and replaced.... so it doesn't matter now...)
And that’s how you can tell the Engineer came out of a corporate line; it doesn’t matter that it was from the old system, obviously the new system was chosen because it was backwards compatible with the old spares to defray the initial maintenance supply costs. And also the cost of shipping complete sets of spares to every maintenance depot they have a contract with.
Or perhaps more similar to the situation of hacking a Win95 box to be a mainframe for a set of C64s because Accounting says IT doesn’t need that many new computers, you already have computers! They need the new computers to run the new accounting software that IT hasn’t seen the specs for... oh, I’ve heard some stories.
Anyways. A Free Trader would just pony up the cash to buy new spares for the new system, and maybe sell or salvage the old ones, while a corporate line is going to have a series of backwards compatible systems that accumulate out-of-date spares that you don’t have permission to sell just yet; this sort of thing could explain why in some editions it takes a lot of volume of spare parts to fix some relatively minor damage - it’s an assorted bundle of hopefully compatible spare parts, which you don’t realize until you’ve got to fit Slot A with Tab B, only to find out that you’ve got Tab A and Tab B, both using separate data bus standards and you just used the last of those adaptors on the last jury-rig. And then you realize that your current project requires a male-to-male 3phase to 1phase power jumper.
Honestly, the Engineering Locker is going to have some horrifying contents.
Which inspires...
(Category: maybe useful? And maybe complete nonsense) - “X system” Inline Firmware/Connector Adaptor-Upgrade Kit; a collection of 200 data-connection adapters (between approximately 5 different connection standards) for a single system on the ship, with the ability to program them to function as additional inline processors, usually to force compatibility between the systems firmware and the actual control systems. It also gets used to add new upgrade kits without having to replace the whole system. 40 of them are missing, and a maintenance check will show roughly 25 to be in use for completely different systems, and none in use on the system they were designed for.