Does bootloader unlock ignore signature verification for Secureboot or AVB?

I can't seem to find this information anywhere. I'm not quite sure if "Bootloader unlock" is ignoring secure boot or if it's ignoring Android Verified Boot. For the sake of convenience, let us discuss using Qualcomm SoCs. In Qualcomm design, PBL, XBL, and some others would need to be verified by a certificate chain, where the root cert is verified by a fused hash value. Source: https://www.qualcomm.com/content/dam/qcomm-martech/dm-assets/documents/secure-boot-and-image-authentication-version_final.pdf Because the image is about secure boot in general and not necessarily in the perspective of Android, if we want to discuss with Android, the "OS Bootloader" would be the Android bootloader (ABL). From the Android bootloader, the Android verifies the boot partitions with dm-verity. Which of these does the bootloader unlock ignore? 1. Verification of XBL, QTEE, ABL, etc that are verified with the fused root hash 2. Verification of boot images that the are verified by the Android bootloader I would assume the use of fastboot only affects the ABL and thus the answer would be #2, but I can't find an answer to confirm this. Are there any documents or books that explain this in detail?