The USB4 spec is available from https://www.usb.org/documents and has been updated recently. Is there something interesting in that older version?
The Alpine Ridge datasheet was posted to MacRumors previously #1,319 .
Thanks for the Titan Ridge datasheet. I wonder how the list of registers differs between Alpine Ridge and Titan Ridge? PDFs are hard to extract tables from though so it's not easy to compare.
Goshen Ridge has a USB4 host controller interface, PCI class code 0c:03:40 so the USB4 spec should apply. I guess the question is what non-USB4 spec stuff does Goshen Ridge have.