It can be anything! An apex, subdomain, or even a URL.
Results for*.security.live.com.office.rp-o365.agircarrco.myshn.eu
www.*.security.live.com.office.rp-o365.agircarrco.myshn.eusecurity.live.com.office.rp-o365.agircarrco.myshn.eulive.com.office.rp-o365.agircarrco.myshn.eucom.office.rp-o365.agircarrco.myshn.euoffice.rp-o365.agircarrco.myshn.eurp-o365.agircarrco.myshn.euagircarrco.myshn.eumyshn.eueu