Clock fallback lists ntp.omarchy.org
Pull request 16247, merged into quattro, sets the clock's fallback to ntp.omarchy.org and then time.cloudflare.com. The Omarchy name is a CNAME to 2.arch.pool.ntp.org, the Arch pool the machines use now.
time.cloudflare.com answers if ntp.omarchy.org does not resolve or no server replies. The fallback stays below a server an administrator sets and below servers a network hands out.
Nothing migrates a running clock: timesyncd reads the list the next time it starts, at the next boot. A drop-in under /etc overrides it.