In the motd of the current install CD (install-amd64-minimal-20150924.iso is what I booted), the link to the handbook still points to the handbook of the old website (not the "new" handbook on the wiki site) and therefore you'll get a 404 when trying to open it.
*** Bug 577986 has been marked as a duplicate of this bug. ***
Also affects me with install-amd64-minimal-20161006.iso
*** Bug 630768 has been marked as a duplicate of this bug. ***
Guys, really? Nearly two years and you can't fix a single text file in the release media? This is quite shameful for us as Distro.
This is fixed in catalyst-3.something (awaiting release & stabilization) but this could also be worked around locally on the autobuild setup via "livecd/motd:" in the spec. I do not know how the FS layout is on the autobuild servers or I'd attach a spec patch myself.
This is fixed in the last several iso builds