Optional ReadonlylayerLayer ids to carry. They keep the order they have in the live style, above the basemap.
Optional ReadonlysourceSource ids to carry with them. A source a carried layer reads is carried anyway; declaring it says so outright.
Engine layers and sources placed on the map OUTSIDE the adapter — by a capability or a plugin that talks to the engine directly — as declared through
IMapAdapter.declareOwnedStyleIds(), so that a basemap switch replacing the style carries them.