At the bottom of https://otrs-wiki.wikimedia.org/ you can see that there is a link called "Confidentiality notice” https://otrs-wiki.wikimedia.org/wiki/Project:General_disclaimer. What is stated in that confidentiality notice is also confidential, since it is located on the wiki. But https://phabricator.wikimedia.org/L45 is the actual agreement singed by OTRS agents to gain access ot he OTRS software and the wiki.
It is also stated in the footer of https://otrs-wiki.wikimedia.org/: "Please be aware that this is a private wiki, so content should not be shared externally.”
-- Jonatan Svensson Glad Josve05a