USB class 0x13 — Bulk Display
Class code 0x13 marks a device or interface as Bulk Display. Operating systems read this value from the descriptor and bind a generic class driver, which is why most bulk display hardware works without a vendor driver even when the VID:PID pair is unrecognised.
How it appears on your system
$ lsusb -v
bInterfaceClass 19 Bulk DisplayWindows exposes the same value in the compatible IDs list as USB\Class_13, extended with &SubClass_xx&Prot_xx for the subclass and protocol below.
Looking up a specific device instead? Search by VID:PID or browse the vendor directory.