Geralmente, isso é ntp (o daemon chamado ntpd ) para o Network Time Protcol.
Por exemplo:
No Fedora, você pode estar procurando
timedatex.service
relacionado a este pacote:
timedatex is a D-Bus service that implements the org.freedesktop.timedate1
interface. It can be used to read and set the system clock, the real-time clock
(RTC), the system timezone, and enable or disable an NTP client installed on
the system. It is a replacement for the systemd-timedated service.