Go the theme_more config Set a value on each colour field, and save Reload the settings page Set all the colours to an empty value Save and make sure the empty value was saved Install theme_magazine: https://github.com/moodlehq/moodle-theme_magazine Go to its settings page, fill in every colour field and save Once back on the page, remove all the colours from the fields, and save Make sure that the colours with a Default value are populated with that value