SharePoint has a tendency to provide WebDAV clients with HTML representations of resources when requests are missing a "Translate: f" header.

Here's a discussion about it on the neon list: http://comments.gmane.org/gmane.comp.web.webdav.neon.general/845

The header is documented at <http://msdn.microsoft.com/en-us/library/cc250216%28v=prot.20%29.aspx>.

Adding this to requests shouldn't have any effect on non-IIS/SharePoint servers, but will enable users to properly mount SharePoint document libraries.