During installation on a headless system (Ubuntu) some plain CSS code is displayed in the console. The installer is here - https://bintray.com/existdb/releases/download_file?file_path=exist-installer-5.1.1.jar
Run `java -jar exist-installer-5.1.1.jar -console` or `java -jar exist-installer-5.1.1.jar` from a terminal on a linux system without X11 installed.
Originally reported here - https://github.com/eXist-db/exist/issues/3160
Maybe related to https://izpack.atlassian.net/browse/IZPACK-974, but we get the CSS appear in the terminal whether we specify `-console` or not. See the attached screenshot