One of the advantages of UrBackup is that it mirrors the filesystem structure of the client for each backup. (I.e. you have snapshots of the clients on the server).
So you can use practically every way of sharing files/folders to make the file backups accessible. If you want to restore something you can simply copy it over.
For example via e.g.: WebDAV, Pydio, samba/Windows file sharing, SCP, sshfs, …
I personally would prefer having it available via Windows explorer, i.e. via WebDAV or samba/Windows share.
That said, UrBackup Server 1.4 already includes a feature to download whole folders as zip file from the web interface.