systemd-localed (8) - Linux Manuals
systemd-localed: Locale bus mechanism
systemd-localed.service, systemd-localed - Locale bus mechanism
systemd-localed.service is a system service that may be used as mechanism to change the system locale settings, as well as the console key mapping and default X11 key mapping. systemd-localed is automatically activated on request and terminates itself when it is unused.
The tool localectl(1) is a command line client to this service.