Custom world generation/template pool


 * The root tag
 * The namespaced id of the pool
 * Can set to another template pool, which generates when the original pool cannot generate at the end of all layers. Used in the vanilla datapack to generate the end of village streets, aka terminators in structure files.
 * A list of structures to choose from
 * How likely this element is to be chosen when using this pool
 * The properties of this element
 * The namespaced id of the structure to place
 * Can be or
 * Can be to generate no structure,  when feature is used,  when elements are used, and  or  when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The namespaced id of the processor to use
 * A list of structures to choose from
 * How likely this element is to be chosen when using this pool
 * The namespaced id of the structure to place
 * Can be or
 * Can be to generate no structure,  when elements is used, and  or  when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The namespaced id of the processor to use
 * Can be to generate no structure,  when elements is used, and  or  when location is used
 * The namespaced ID of a processor if this is a string
 * A list of processors to use
 * The namespaced id of the processor to use
 * The namespaced id of the processor to use