Format "guid" vs "uuid"

[david-brink-talogy]

The OpenAPI format registry and JSON Schema docs indicate "uuid" is supported, but not "guid". When using NSwag to generate OpenApi docs for an Asp.Net core API, properties of type System.Guid use a schema with "format": "guid" by default. Is there a reason that NJsonSchema and by extension NSwag prefer a format not defined by the standards body?

JsonFormatStrings.Uuid is also marked as obsolete.