Little update: I added the keyboard-configuration/layoutcode=de parameter to the preseed boot kernel command line and got a little bit different result:
1. In lightdm there is only the German keyboard.
2. In a freshly created user there is Germand and English keyboard. That user did not have any home directory before.
The content of /etc/default/keyboard did not change.
Little update: I added the keyboard- configuration/ layoutcode= de parameter to the preseed boot kernel command line and got a little bit different result:
1. In lightdm there is only the German keyboard.
2. In a freshly created user there is Germand and English keyboard. That user did not have any home directory before.
The content of /etc/default/ keyboard did not change.