In the web page there is a sentence to describe tty drivers.
The /proc/tty/drivers file shows all of the currently registered tty drivers.
Here is some info about w and /proc/tty/drivers.
debian8@hwy:~$ w
23:53:38 up 2 min, 1 user, load average: 0.47, 0.46, 0.20
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
debian8 :0 :0 23:51 ?xdm? 4.62s 0.05s /usr/bin/lxsess
debian8@hwy:~$ cat /proc/tty/drivers
/dev/tty /dev/tty 5 0 system:/dev/tty
/dev/console /dev/console 5 1 system:console
/dev/ptmx /dev/ptmx 5 2 system
/dev/vc/0 /dev/vc/0 4 0 system:vtmaster
serial /dev/ttyS 4 64-95 serial
pty_slave /dev/pts 136 0-1048575 pty:slave
pty_master /dev/ptm 128 0-1048575 pty:master
unknown /dev/tty 4 1-63 console
Which line in the /proc/tty/drivers reflect w command?
:0
is Xorg which isn't a tty. That's just the column where a tty would be listed if the user were on one.