I found this landoflinux.com tutorial the simplest to understand. You can run the following command yourself to see what's there:

$ ls -al /lib/systemd/system/runlevel*
lrwxrwxrwx. 1 root root 15 Apr 25 10:31 /lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 Apr 25 10:31 /lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel6.target -> reboot.target

But you should probably just read the linked question accepted answer about targets.

I found this landoflinux.com tutorial (webarchive) the simplest to understand. You can run the following command yourself to see what's there:

$ ls -al /lib/systemd/system/runlevel*
lrwxrwxrwx. 1 root root 15 Apr 25 10:31 /lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 Apr 25 10:31 /lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel6.target -> reboot.target

But you should probably just read the linked question accepted answer about targets.

I found this tutorial the simplest to understand. You can run the following command yourself to see what's there:

$ ls -al /lib/systemd/system/runlevel*
lrwxrwxrwx. 1 root root 15 Apr 25 10:31 /lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 Apr 25 10:31 /lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel6.target -> reboot.target

But you should probably just read the linked question accepted answer about targets.

I found this landoflinux.com tutorial the simplest to understand. You can run the following command yourself to see what's there:

$ ls -al /lib/systemd/system/runlevel*
lrwxrwxrwx. 1 root root 15 Apr 25 10:31 /lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Apr 25 10:31 /lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 Apr 25 10:31 /lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 Apr 25 10:31 /lib/systemd/system/runlevel6.target -> reboot.target

But you should probably just read the linked question accepted answer about targets.