code/modules/research/stock_parts/stock_part_datum.dm 
| /datum/stock_part | Represents the concept of a stock part.
One is created for every stock part type for every level.
Machines have these inside their component_parts.
For example, scanning modules use /datum/stock_part/scanning_module.
In machines, you can perform a loop through something like
for (var/datum/stock_part/scanning_module/part in component_parts) |
|---|---|
| /datum/stock_part/ansible | Subspace stock parts |