warnings
Had the following warnings during execution:
Adding your new secret key to LUKS. When prompted, type in your OLD passphrase to unlock the disk. Geben Sie irgendeine bestehende Passphrase ein: update-initramfs: Generating /boot/initrd.img-4.19.0-5-amd64 cryptsetup: WARNING: Resume target luks-xyzabc uses a key file WARNING: Unknown X keysym "dead_belowmacron" WARNING: Unknown X keysym "dead_belowmacron" WARNING: Unknown X keysym "dead_belowmacron" WARNING: Unknown X keysym "dead_belowmacron" GRUB-Konfigurationsdatei wird erstellt … Warnung: GRUB_TIMEOUT auf einen von Null verschiedenen Wert setzen, wenn GRUB_HIDDEN_TIMEOUT als nicht mehr unterstützt angegeben wird.
What do they mean and do I have to take further measure?
For the grub warning I already found the explanation in info -f grub -n 'Simple configuration'
section about GRUB_HIDDEN_TIMEOUT:
This option is unset by default, and is deprecated in favour of the less confusing 'GRUB_TIMEOUT_STYLE=countdown' or 'GRUB_TIMEOUT_STYLE=hidden'.
...and uncommented the GRUB_HIDDEN_TIMEOUT lines in /etc/default/grub.