Is it possible to remove a sub-theme so that it does not appear in the theme list when invoking load-theme or customize-themes?
For instance removing only doom-spacegrey from the doom theme-set, while keeping the other sub-themes.
A related question is whether it is possible to install only a deliberate subset of sub-themes from a main theme.
doom-spacegrey is part of doom-themes package. It's not a "sub-theme" but file included in package.
You can remove doom-spacegrey-theme.el from ~/.emacs.d/elpa/doom-themes-<version>/. But it will appear again on doom-themes package update.
Better solution would be to add advice around custom-theme-name-valid-p function which is used by custom-available-themes to filter out valid theme names:
(defvar my/blacklisted-themes '("doom-spacegrey"))
(defun my/theme-allowed (orig-fun theme-name)
(and (funcall orig-fun theme-name)
(not (member (symbol-name theme-name) my/blacklisted-themes))))
(advice-add 'custom-theme-name-valid-p :around #'my/theme-allowed)
Although theme isn't actually removed it will not appear in the list of available themes.
