The build.sh shell script “compresses” the value sets obtained from the GitHub repo collecting them from primary sources to a dictionary mapping value set ID → (an array of) value set IDs.
The GitHub Action “Value Sets Compression” executes this script, and exposes the compressed value sets JSON as artifact.
The compressed value sets form the valueSets part of the external data input validation rules executing on.
The script relies on git, and the jq tool to function.
On macOS, the latter can be installed as follows using Homebrew:
$ brew install jq