Every published layer is a standalone GeoTIFF. The API describes the inventory; the file URL is the data contract.
API endpoints
GET/api/years
GET/api/variables
GET/api/summary
GET/api/download/{year}/{file}?dataset=9km|1km
GET/api/scripts?start=X&end=Y&fmt=bash|urls
Base URL: https://data.xbioclim.org