When on https://wiki.documentfoundation.org/Litmus webpage, under the Introduction, clicking on link titled "Litmus", which leads to https://tcm.documentfoundation.org/ results in DNS name look up error.
At the top of that wikipage you see "Litmus is no more in use by the community, we use Moztrap instead, so the contents of this page is outdated." Since that webpage simply no longer exists and Litmus is no longer in use, I removed the link in question. In those minor cases, feel free to create a wiki account if you want. And fix things yourself. Wiki editing is a nice task to get started participating. :)
That makes sense, thank you. The LibreOffice Help page should be updated to reflect that change as well, because in the instructions for how to help as a QA in Manual Testing, it still refers to Litmus. (https://www.libreoffice.org/get-involved/qa-testers/)