[USB] endpoint_queue_head pointer4 values if EXPERIMENTAL_INTERFACE is set

[forderud]

Sorry if asking a newbie question, but I'm trying to understand the thinking behind the pointer4 values used in the endpoint0_setup function when EXPERIMENTAL_INTERFACE is defined (introduced in abff6cb):

endpoint_queue_head[2].pointer4 = 0xB8C6CF5D;
endpoint_queue_head[3].pointer4 = 0x74D59319;

Are 0xB8C6CF5D and 0x74D59319 arbitrary values, or do they have a special meaning?

It would also be great if the bInterfaceProtocol=0xC7 value for the EXPERIMENTAL_INTERFACE could be explained with a comment. Is this a Microsoft-defined protocol code for WinUSB devices, or something else?