Add comments

init.lua

@@ -1556,14 +1556,16 @@ local function get_init_items()
 		if name ~= "" and show_item(def) then
 			cache_drops(name, def.drop)
 
-			if not fuel_cache[name] then
+			if not fuel_cache[name] then --[*]
 				cache_fuel(name)
 			end
 
-			if not recipes_cache[name] then
+			if not recipes_cache[name] then --[*]
 				cache_recipes(name)
 			end
 
+			--[*] `core.register_craft` override may have cached them already
+
 			_preselect[name] = true
 		end
 	end