The "kio" library of the "K Desktop Enviroment"
(<http://www.kde.org/>) uses the URI scheme "webdav" to dispatch to
the system's WebDAV client. This URI scheme is not registered, nor
is it supported on other platforms. Furthermore, the W3C's
"Architecture of the World Wide Web, Volume One" explicitly advises
against defining new schemes when existing schemes can be used:
A specification SHOULD reuse an existing URI scheme (rather than
create a new one) when it provides the desired properties of
identifiers and their relation to resources.
(See [WEBARCH], Section 2.4.)