An article by Jeff Benjamin at 9to5 mac speculates on the ‘compute module’ in iOS 16.4 code.
I hope it really is for the Mac Pro, but honestly I doubt it. I think the Mac Pro will be a higher end Mac Studio, with more Thunderbolt ports. After the seeming upgrade-ability of the last Mac Pro which only had PCI slot upgrades, I just doubt they are making some upgrade-able aspect to the Mac Pro.
It seems much more likely to be a processor for the Reality Pro headset.