Bills of Materials work with hardware because origins can be tracked. Good luck tracking the origin of electrons. I worked in manufacturing for a company the dealt solely with MilSpec (Military Specification). Crates sent to Nuclear Power plants had to X-Rayed on the shipping dock and then again at the receiving dock. If the X-Rays differed in any questionable way the shipment was rejected. However, most supply chains are not that paranoid. In the 1980s there was a grade eight bolt scandal for a satellite that blew up in space because the manufacturer substituted plain steal to make more money. More recently the BOM did nothing to protect the Bay Area Bridge where once again bolts as well as rods were specified of one quality and delivered as another. The bolts and rods are still in the new span because taking them out would require tearing it down again. But the builder assures us things are fine, wink wink, nod nod. https://www.courthousenews.com/34m-settlement-reached-for-de...