According to the product page for the USB-C expansion card, “on Ryzen platforms, protocols depend on the specific Expansion Bay.”
This information does not seem easily available - at least some lazy searching did not find anything meaningful, just unrelated discussions. For the available and pre-order Ryzen boards, what features are supported for each expansion bay card?
If you mean for the 13 you can preorder at the moment, it doesn’t have an expansion bay but if you mean the expansion cards, the capabilities of each port are listed on the product page under “interfaces”.
Basically the 2 top ports full featured USB4 (so basically TB4 without the intel cert), bottom right USB3.2+DP and bottom left just usb 3.2.
What isn’t on the product page (but on the product page of the chipset which is a lot harder to find) is that both USB4 ports have their own 40gbit uplink to the cpu so no bandwidth sharing between them.