helloworldPipeline is an open-source SyncroSim base package, part of the helloworldEnhanced package suite. It was designed as a basic example of how to use model pipelines in a custom SyncroSim package, such that the output from one model can be used as the input for the next model.
For more information, see the Enhancing a Package tutorial in the SyncroSim documentation or the helloworldEnhanced website.