OnePlus 8T:
KB05AA tools (international firmware):
android os 11: Oxygenos
KB05BA tools (european firmware):
android os 11: Oxygenos
KB05DA tools (indian firmware):
android os 11: Oxygenos
KB09CB tools (USA T-Mbile firmware):
android os 11: Oxygenos
tools (China firmware):
android os 11: ColorOS