Hierarchical time series documentation?

Is there any supporting docs as to how the hierarchical time series functionality in automl functions? Meaning, does it implement reconciliation techniques, or does it rely on higher-level features included at each lower level of the hierarchy?

Search the repository and Azure Machine Learning guidance for “hierarchical time series” and AutoML. Establish whether reconciliation is implemented or whether lower-level forecasts are combined, then add a concise explanation with links to the relevant documentation. Done means a reader can understand the behavior without relying on an unanswered issue.

Written by the indexing model from the issue text.