Joomla 5.0.0. Code Mirror is chosen. See how it looks like in Dark mode. And there is no button to switch to Light mode. But would be better to add special styles for Code Mirror making it compatible to dark mode.
Closing as duplicate report. See #42148 just a few rows below this one here.
… and #42134 for the switching off dark mode part.
Closing as duplicate report. See #42148 just a few rows below this one here.