Minecraft wiki entry for Processor_list, associated text:  rules: The rules to apply.
: Root tag of a single rule.
 A rule
 position_predicate (optional): The position rule to apply to the block. Defaults to minecraft:always_true.
 input_predicate: The rule to apply to the block that is placed.
 location_predicate: The rule to apply to the block before the structure is generated [needs testing]
 output_state: The block that is placed if all conditions are met.
 Name: ID of the block
 Properties: Block states
 state: A block state key and its value
 output_nbt (optional): The NBT data of the block placed if all conditions are met [needs testing]. Unused in vanilla.