3GPP 23.501 v20.2.0 — the document's own text
5.16.4.2 Architecture Reference Model for Emergency Services
Taught in 21. Emergency calls, messages, voice and location (The 5G system architecture, in depth).
According to clause 4.2, the non-roaming architectures (Figure 4.2.3-1 and Figure 4.2.3-2) and roaming architecture with the visited operator's application function (Figure 4.2.4-1 and Figure 4.2.4-4) apply for Emergency Services. The other non-roaming and roaming architectures with services provided by the home network do not apply for Emergency Services.