Browse a URL as a WebDAV share. With the Tampermonkey extension on Firefox Mobile you can use it from phone.
Open WebDAV folder in a browser and you'll have ether 403 error or just a plain directory listing.
Then click on the addon button and it will make a file manager from the folder where you can watch, upload, delete files and direcotries.
The script automatically enables for any url that have /dav/
e.g. http://example.com/dav/
prefix or dav.
subdomaain e.g. http://dav.example.com/
.