Minecraft wiki entry for Development_versions, associated text: Predicate now accepts block and fluid sub-predicate.
Fields:
block – exact block ID to match.
fluid – exact fluid ID to match.
tag – block/fluid ID to match.
nbt – matcher for block entity NBT (only for blocks).
state – map of name/value properties. Value can be integer, boolean or string or object with optional min and max properties.
Predicate now accepts the light sub-predicate.
Object has one integer range – light – that matches visible light (maximum value of sky-darkening and block light).