The OpenAPI Spec allows for specification extensions (fka vendor extensions) which are properties that start with the
x- naming convention.
Redocly has implemented some specification extensions which augment functionality.
Some are specifically used to bridge between version 2 and 3 of the OpenAPI spec:
And to bridge between version 2/3.0 and 3.1:
Learn about how to use specification extensions for other purposes such as hiding an API path, operation, or schema property.