A string specifying a type for choose elem buttons. It's also used by ElemID for LuaGuiElement::elem_tooltip.
"achievement" | "decorative" | "entity" | "equipment" | "fluid" | "item" | "item-group" | "recipe" | "signal" | "technology" | "tile" | "asteroid-chunk" | "space-location" | "item-with-quality" | "entity-with-quality" | "recipe-with-quality" | "equipment-with-quality"