Yes, those were proprietary HP Foxconn units designed more for server pc use than gaming pc use. 2x 15A cpu outputs and 3x 12v 12A/9A/9A outputs. Good for multiple cpus/drives, bad for a gpu beyond pcie powered.
Pretty much they'll only bolt up directly to the Old HP case they originally came in. Anything else will require a modification plate built from scratch to fit.
Edit: considering you can get them all day long on ebay for $19-$29, their use in Any modern pc would be strongly not recommended at all.