What this means
The IEEE assigned the MA-L block FCB387 to Leapmotor (Jinhua) New Energy Vehicle Parts Technology Co., Ltd.. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting FC:B3:87, it is Leapmotor (Jinhua) New Energy Vehicle Parts Technology Co., Ltd. hardware.