Convert SysV init run level S to Systemd *.target (Debian)

I am converting a SysV init style file to Systemd Unit file and it's init section block looks like this: ### BEGIN INIT INFO # Provides: ifcheck # Required-Start: $local_fs # Required-Stop: # Should-Start: # Should-Stop: # Default-Start: S # Default-Stop: # Short-Description: Network interfaces check & replace # Description: Checks if the interfaces were corrupted or if the special section is missing. If so, a default version will be copied over. ### END INIT INFO I know that run levels 0-6 correspond to various systemd targets: ╔══════════════════════╦═══════════════════╗ ║ Run Level (SysVinit) ║ Systemd Target ║ ╠══════════════════════╬═══════════════════╣ │ Run level 0 │ poweroff.target │ ├──────────────────────┼───────────────────┤ │ Run level 1 │ rescue.target │ ├──────────────────────┼───────────────────┤ │ Run level 2 │ multi-user.target │ ├──────────────────────┼───────────────────┤ │ Run level 3 │ multi-user.target │ ├──────────────────────┼───────────────────┤ │ Run level 4 │ multi-user.target │ ├──────────────────────┼───────────────────┤ │ Run level 5 │ graphical.target │ ├──────────────────────┼───────────────────┤ │ Run level 6 │ reboot.target │ ├──────────────────────┼───────────────────┤ │ Emergency │ emergency.target │ └──────────────────────┴───────────────────┘ (According to https://www.tecmint.com/change-runlevels-targets-in-systemd/ ) But I have never seen S as a run level before. I've seen some definitions that says it is for single-user while there are others that define it as a synonym for other run levels and still others don't have a conclusive defintion . I know the version I am working with is most likely the **Linux Standard Base specification** because immediately after the init info block is the sourcing of the **lsb init functions** (Sourced via . /lib/lsb/init-functions). Also the system is running Debian 8 Jessie. **What target should I put in the equivalent systemd unit file for run level S?**