Nextcloud: \OCA\DAV\CardDAV\ImageExportPlugin allows serving arbitrary data with user-defined or empty mimetype

The SabreDAV plugin \OCA\DAV\CardDAV\ImageExportPlugin is used for displaying pictures of a VCF. It registers on a GET request on a CardDAV element and acts when the query parameter photo is sent. The logic can be seen below: / Intercepts GET requests on addressbook urls ending with ?photo. @para...