Fontaine is now a “theme” In the past, this was done in a way that could get overridden under certain conditions, such as by loading a theme after setting a Fontaine preset configuration. Fontaine is a theme in the same way use-package is, meaning that it will (i) persist its effects, (ii) not show up in the custom-enabled-themes and so not be affected by something like (mapc #'disable-theme custom-enabled-themes) , and (iii) not be an option among those presented by load-theme .