This is the mechanism by which one unit can ask to be added to the Wants= of another when it is installed.
i.e., when you run 'systemctl enable whatever.service', it will be symlinked into '/etc/systemd/system/multi-user.target.wants'. And 'systemctl show multi-user.target' will show 'whatever.service' in its Wants property.
During bootup of a headless system, the 'default' target is usually multi-user.target, so what we've done here is ensure that whatever.service will be started before the machine finishes booting.
i.e., when you run 'systemctl enable whatever.service', it will be symlinked into '/etc/systemd/system/multi-user.target.wants'. And 'systemctl show multi-user.target' will show 'whatever.service' in its Wants property.
https://www.freedesktop.org/software/systemd/man/systemd.uni...
During bootup of a headless system, the 'default' target is usually multi-user.target, so what we've done here is ensure that whatever.service will be started before the machine finishes booting.
https://www.freedesktop.org/software/systemd/man/bootup.html