Adam Conrad points out that all the other /dev/tty[0-9]* have group tty ownership. However, they are 0620:
$ ls -l /dev/tty10
crw--w---- 1 root tty 4, 10 Apr 13 09:29 /dev/tty10
This is presumably from the udev default in /lib/udev/rules.d/50-udev-default.rules:
KERNEL=="tty[0-9]*", GROUP="tty", MODE="0620"
Adam Conrad points out that all the other /dev/tty[0-9]* have group tty ownership. However, they are 0620:
$ ls -l /dev/tty10
crw--w---- 1 root tty 4, 10 Apr 13 09:29 /dev/tty10
This is presumably from the udev default in /lib/udev/ rules.d/ 50-udev- default. rules: ="tty[0- 9]*", GROUP="tty", MODE="0620"
KERNEL=