code/controllers/subsystems/overlays.dm 
| /var/ATOM_ICON_CACHE_NORMAL | SSoverlays. Target the normal overlay cache. |
|---|---|
| /var/ATOM_ICON_CACHE_PROTECTED | SSoverlays. Target the protected overlay cache. |
| /var/ATOM_ICON_CACHE_ALL | SSoverlays. Target both normal and protected overlay caches. |