Source (link to git-repo or to original if based on someone elses unmodified work): https://devel.trisquel.info/teodorescup/plymouth-theme-placidity/tree/10.2
Placidity plymouth theme with Debian logo.
Tested with plymouth: 0.9.4-1 .
The source for the background image is https://pxhere.com/ro/photo/1440683
sudo tar xf plymouth-theme-placidity_10.2.tar.gz -C /usr/share/plymouth/themes
sudo chown -R 0:0 /usr/share/plymouth/themes/placidity
sudo plymouth-set-default-theme -R placidity