I found a partial answer myself by finding the force-level1-csd.sh script, and digging through. That combined with
this link showed me the following:
(1) That shell script, force-level1-csd.sh is responsible for the command by the same name.
(2) The script expects a metadata folder with the same name as the directory on GCS on your machine. This folder should be accessible by the path name from the current directory. See the update_meta() function in the file for more context.