The Linux colorscheme is unusable on white background, yellow on white is a pain to look at, whereas the LightBG background is readable on black. So the LightBG is the lesser of two evil.
It is easy enough to change via %colors <name> in the console, the --colors command line flag and c.TerminalInteractiveShell.colors configuration. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org