It can be anything! An apex, subdomain, or even a URL.
Results forosi.office.net.mvision.yj-o365-and-onedrive.bt.myshn.eu
www.osi.office.net.mvision.yj-o365-and-onedrive.bt.myshn.euoffice.net.mvision.yj-o365-and-onedrive.bt.myshn.eunet.mvision.yj-o365-and-onedrive.bt.myshn.eumvision.yj-o365-and-onedrive.bt.myshn.euyj-o365-and-onedrive.bt.myshn.eubt.myshn.eumyshn.eueu