The terms to search for are fan-out wafer level packaging (FOWLP) and TSMC InFO. The chiplets come from different wafers and are reconstituted into a molded plastic wafer, allowing multiple die side-by-side. Then multiple layers of wires are built on top, terminating in a BGA.
My astonishment at these manufacturing processes is never-ending.
Ok, part of my confusion was that it was being presented in contrast to InFO-oS and InFO-PoP, but it appears to mostly be a modified version of InFO-PoP called InFO-M? Because Apple has been using InFO-PoP for almost a decade at this point, starting with the A10.