diff --git a/data/builtin.lua b/data/builtin.lua
new file mode 100644
index 000000000..ead1ed3a6
--- /dev/null
+++ b/data/builtin.lua
@@ -0,0 +1,102 @@
+function basic_dump2(o)
+	if type(o) == "number" then
+		return tostring(o)
+	elseif type(o) == "string" then
+		return string.format("%q", o)
+	elseif type(o) == "boolean" then
+		return tostring(o)
+	elseif type(o) == "function" then
+		return "<function>"
+	elseif type(o) == "userdata" then
+		return "<userdata>"
+	elseif type(o) == "nil" then
+		return "nil"
+	else
+		error("cannot dump a " .. type(o))
+		return nil
+	end
+end
+
+function dump2(o, name, dumped)
+	name = name or "_"
+	dumped = dumped or {}
+	io.write(name, " = ")
+	if type(o) == "number" or type(o) == "string" or type(o) == "boolean"
+			or type(o) == "function" or type(o) == "nil"
+			or type(o) == "userdata" then
+		io.write(basic_dump2(o), "\n")
+	elseif type(o) == "table" then
+		if dumped[o] then
+			io.write(dumped[o], "\n")
+		else
+			dumped[o] = name
+			io.write("{}\n") -- new table
+			for k,v in pairs(o) do
+				local fieldname = string.format("%s[%s]", name, basic_dump2(k))
+				dump2(v, fieldname, dumped)
+			end
+		end
+	else
+		error("cannot dump a " .. type(o))
+		return nil
+	end
+end
+
+function dump(o, dumped)
+	dumped = dumped or {}
+	if type(o) == "number" then
+		return tostring(o)
+	elseif type(o) == "string" then
+		return string.format("%q", o)
+	elseif type(o) == "table" then
+		if dumped[o] then
+			return "<circular reference>"
+		end
+		dumped[o] = true
+		local t = {}
+		for k,v in pairs(o) do
+			t[#t+1] = "" .. k .. " = " .. dump(v, dumped)
+		end
+		return "{" .. table.concat(t, ", ") .. "}"
+	elseif type(o) == "boolean" then
+		return tostring(o)
+	elseif type(o) == "function" then
+		return "<function>"
+	elseif type(o) == "userdata" then
+		return "<userdata>"
+	elseif type(o) == "nil" then
+		return "nil"
+	else
+		error("cannot dump a " .. type(o))
+		return nil
+	end
+end
+
+--
+-- Built-in node types. Also defined in C.
+--
+
+minetest.register_node("air", {
+	drawtype = "airlike",
+	paramtype = "light",
+	light_propagates = true,
+	sunlight_propagates = true,
+	walkable = false,
+	pointable = false,
+	diggable = false,
+	buildable_to = false,
+	air_equivalent = true,
+})
+
+minetest.register_node("ignore", {
+	drawtype = "airlike",
+	paramtype = "none",
+	light_propagates = false,
+	sunlight_propagates = false,
+	walkable = false,
+	pointable = false,
+	diggable = false,
+	buildable_to = true, -- A way to remove accidentally placed ignores
+	air_equivalent = true,
+})
+