Problems changing default chmod of /dev/pts/*

[Decstasy]

Hello,

I want to change the default chmod of /dev/pts/* from 620 to 660. In the 
past it can be changed by /etc/defaults/devpts
But it does not work at all. I could not find any entry in /etc/fstab or 
a mount unit from systemd.
I have also checked /etc/init.d/udev and /etc/init.d/mountdevsubfs.sh
----SNIP----
root@minecraft ~ # cat /etc/issue; uname -a
Debian GNU/Linux 8 \n \l

Linux minecraft 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 
(2015-11-09) x86_64 GNU/Linux
root@minecraft ~ # find /etc/systemd -name '*mount'
root@minecraft ~ # find /etc/systemd -name '*.device'
root@minecraft ~ # find /var/lib/systemd -name '*mount'
root@minecraft ~ # find /var/lib/systemd -name '*.device'
root@minecraft ~ # grep -ri pts /var/lib/systemd
1 root@minecraft ~ # grep -ri pts /etc/systemd                           
                                                                         
                                                  :(
1 root@minecraft ~ # grep -ri pts /etc/udev                              
                                                                         
                                                  :(
1 root@minecraft ~ # mount | grep pts                                    
                                                                         
                                                  :(
devpts on /dev/pts type devpts 
(rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
root@minecraft ~ # cat /etc/default/devpts
# GID of the `tty' group
TTYGRP=5

# Set to 600 to have `mesg n' be the default
TTYMODE=660
----SNAP----

Where can I change the default chmod?
I hope someone can help me...

Thanks in advance and best regards,
Dennis