The devuan grub package contains debian-ized files:

1] /etc/grub.d/05_debian_theme

This file could be renamed devuan_theme, but some of the current content
would need to be changed or removed. It currently includes a case
statement for "Tanglu|Ubuntu|Kubuntu", which isn't necessary, and the
remaining case statement should be changed to whatever color theme
devuan decides upon.

On that note, I'll chime in and say that I hate the red greeter screen
of the installer.

Further down in the same file is a list of debian-specific background
images, for devuan to remove or replace

2] /etc/default/grub

There is a line in the file beginning 'GRUB_DISTRIBUTOR=', for which you
may want to replace '|| echo Debian' with '|| echo Devuan'


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