KBC stands for Keyboard Controller. This info isn't much help, because the number of people in the tech repair or Dell repair business who can read the code are few indeed. The system used provides KBC data and a KBC flash utility to be combined and embedded into a basic input/output system read-only memory (BIOS ROM). It is not like reading a regular 8 digit password. Your BIOS checks the versions of the KBC data embedded in the BIOS ROM and the KBC in the system. This information is basically useless for most visitors to this forum, but should you know somebody who has the equipment, and the time, and the interest, they can provide you with the probable password so you can enter it yourself next time. If the version of the embedded KBC is newer than the version of the KBC in the system, the KBC flashing process is performed during a POST of the system.
Reading the code is "easy" for the person who is trained. Finding the trained person is still the difficult part.