As a premise, customer board (implemented CCG3) is enumerate as Source and DFP whereas T470s starts with Sink and UFP.
Although I do not know the features of custom FW, customer board might want to become a UFP and T470s sends DR_Swap.
Since there are no information of Configuration and FW, it is just an assumption.
VCONN_Swap will be sent by either Port Partner to request an exchange of VCONN Source role responsibility.
Same as above, no information of Configuration and FW, it is difficult to esimate it.
VDM which stands for Vendor Defined Message is sent from T470s. VDM is provided to allow vendors to exchange information.
VDM is structured Header, VDM Header, and VDOs. The VDM Header provides command space to allow vendors to customize Messages for their own purposes. We are not able to know.
See "6.4.4 Vendor Defined Message" of PD Spec.
Because there are no Data Object such as Power Data Object (PDO), Reqest Data Object (RDO), Vendor Data Object (VDO), etc.
Your next action may two things.
1. Contact with developer for the FW and configuration if you know.
2. Read PD Spec.
Thank you for your reply.