It can be anything! An apex, subdomain, or even a URL.
Results fors.windows.microsoft.com.igor365.m365---mcafeecloud.mcafee.myshn.eu
www.s.windows.microsoft.com.igor365.m365---mcafeecloud.mcafee.myshn.euwindows.microsoft.com.igor365.m365---mcafeecloud.mcafee.myshn.eumicrosoft.com.igor365.m365---mcafeecloud.mcafee.myshn.eucom.igor365.m365---mcafeecloud.mcafee.myshn.euigor365.m365---mcafeecloud.mcafee.myshn.eum365---mcafeecloud.mcafee.myshn.eumcafee.myshn.eumyshn.eueu