modular_aphelion/modules/custom_sprites/code/editor.dm

/datum/config_entry/flag/disallow_custom_sprite_editing	Editing can be disabled without removing any saved appearance.
/datum/preference_middleware/custom_sprites	Character setup's side of the custom sprite editors: opening them, which markings have a drawing, and putting drawings on the character.
/proc/custom_style_rewrite_markings	Rewrites a limb's native marking records. Markings are stored by name, so one limb can't wear the same marking twice, and their order is kept.