One significant, terrible new feature is that they deprecated the `Config` configuration class, and instead, have reserved every field that starts with `model_` for themselves.

WHY. Why did anyone think this was a good idea? Even before AI, the word "model" was everywhere.

Having one reserved field that also started with a capital letter was fine. Reserving an unbounded number of fields for yourself, everything starting `model_`, is a terrible idea.

https://github.com/pydantic/pydantic/issues/6322 for more information.