Based on the Debian 'unstable' branch.
ISO Download:
DebianDog-Sid-openbox_xfce-jwm-2016-11-19.iso
DebianDog-Sid-openbox_xfce-jwm-2016-11-19.md5
Forum post at murga-linux.com (Stretch and Sid):
DebianDog - Stretch Preview
Repository line in /etc/apt/sources.list is set to snapshot.debian (static)
Set it to today's date to be able to get updates, e.g:
deb http://snapshot.debian.org/archive/debian/20161119/ unstable main contrib non-free
Or change if you wish to get always updates to:
deb http://ftp.de.debian.org/debian/ sid main contrib non-free
(then comment out the snapshot.debian line)
And run after any change in /etc/apt/sources.list:
apt-get update