Notice: please refer to the upstream LTSP web site (https://ltsp.org) for the current LTSP 20.04 documentation, or the archived wiki (https://github.com/ltsp/ltsp5/wiki) for the old LTSP 5 documentation.
In 2019, LTSP was redesigned and rewritten from scratch, breaking backwards compatibility. LTSP users were notified to move whatever useful content still existed here to the archived LTSP 5 wiki. When LTSP 20.04 shipped with Ubuntu 20.04, all pages under this UbuntuLTSP wiki were deleted because they were inappropriate, confusing and in some cases even harmful. It was becoming increasingly difficult to support users after they have messed up their systems while following instructions from these pages. Actually most of the pages haven't been maintained since Ubuntu 10.04, so they were unsuitable even for the old LTSP 5 version.
If you really need to find the contents of an old UbuntuLTSP page, you may visit the Wayback Machine.