In the latest version 9.44.0 OptPlanner, for example, there is an example for curriculum course scheduling. I cannot understand the structures of input data files under the folder C:\Program Files\optaplanner\examples\sources\data\curriculumcourse\import, i.e. how to represent constraints and raw data. There is no related doc.
I read the official doc and check the UI and the input data but found no clue.
In Timefold Solver, an actively maintained fork of OptaPlanner, you can no longer find these examples. They are outdated and generally no longer the best way of showcasing the solver's capabilities.
Instead, I recommend you check out Timefold Quickstarts. They're focused on showing only the very basics and removing distractions.