Say Swagger and most people picture the UI: the green-and-black page with every endpoint expandable and an Execute button. That page is generated from an OpenAPI document, which is the part worth owning; the UI is one renderer of it, and Scalar and Redoc are others.
UXLab serves Swagger UI at /_swagger under pnpm dev, beside Scalar at /_scalar, both rendering the same Nitro-generated spec; see OpenAPI.