Besides GET and PUT, WebDAV adds methods such as PROPFIND (list a directory), MKCOL (create a folder), MOVE, COPY and LOCK. Responses often come as 207 Multi-Status with XML. Nextcloud uses WebDAV for the desktop client, mobile apps and network drives under /remote.php/dav/files/user/.
Windows can map WebDAV as a drive, with limitations: the WebClient service caps file size at about 50 MB by default and requires HTTPS for basic auth.
Common errors sit in front of the application: a reverse proxy or WAF blocks unknown methods such as PROPFIND, an upload limit cuts off large files (413), or the /.well-known/caldav and /.well-known/carddav redirects are missing.
Example
curl -u user -X PROPFIND -H 'Depth: 1' https://cloud.example.com/remote.php/dav/files/user/