There is no fbobjclldb.py module which is mentioned in the README.md
Author: LiiisztCreated Jul 22, 2022Updated Apr 2, 2023
In Custom Command, "Chisel has a python function just for this, loadCommandsInDirectory in the fbobjclldb.py module."
Actually, the name of the module is fbchisellldb.py or fblldb.py.
Source: facebook/chisel