What is the syntax used by pip --upload-prior-to

The docs states –uploaded-prior-to<datetime_or_duration> Only consider packages uploaded prior to the given value. Accepts an ISO 8601 datetime (e.g., ‘2023-01-01T00:00:00Z’, uses local timezone if none specified) or a duration in days (e.g., ‘P3D’ for packages uploaded at least 3 days ago). Only effective when using indexes that provide upload-time metadata. (environment variable: PIP_UPLOADED_PRIOR_TO) It unclear what syntax convention it’s using. It would be clearer to add more examples...