[3] PROPPATCH / PROPFIND (RFC 4316 >>4) は xsi:type 属性を使います。

[4] RFC 4316: Datatypes for Web Distributed Authoring and Versioning (WebDAV) Properties, 2022-02-09T09:03:17.000Z https://www.rfc-editor.org/rfc/rfc4316.html#section-5

[1] RFC 5323 - Web Distributed Authoring and Versioning (WebDAV) SEARCH (2017-10-01 13:49:21 +09:00) https://tools.ietf.org/html/rfc5323#section-5.11

[2] RFC 5323 - Web Distributed Authoring and Versioning (WebDAV) SEARCH (2017-10-01 13:49:21 +09:00) https://tools.ietf.org/html/rfc5323#section-5.19.3