For Biolink Model, the main source of truth is the YAML.
If you would like to work with the model in a programmatic way then make use of Biolink Model Toolkit.
It is a python library that provides convenience methods for querying the YAML.
Biolink Model Toolkit provides several methods for accessing and navigating the classes and slots defined in the YAML. It also provides lookup operations that allows easy navigation of various elements in the model.
The toolkit makes use of biolinkml, the same metamodeling framework used for building the model.