Optional screenOptional virtualOptional virtualOptional zStacking order of this renderer's UI relative to the other renderers (the main
one and every addUiRenderer). Higher values render in front. When omitted,
renderers stack in the order they first render, later ones on top; among those
first rendered in the same tick the main UI goes at the back.
It is applied to the renderer's root container entity, so it only orders whole
renderers against each other; elements inside a renderer keep their own zIndex.
Screen area the renderer's UI is positioned in. Defaults to
'device', so UI stays inside the device safe area unless the creator opts out with'none'. Each renderer honors its own value, so the main UI and additional renderers can use different insets simultaneously.