Schema Name: index.xsd This is the root 'index' schema for the Biodiversity dataflow. Always available as http://services.natureserve.org/docs/schemas/biodiversityDataFlow/1/, it's only job is to point to the latest version of the Biodiversity dataflow schema. In the current case, this is '1/BiodiversityDataFlow_v1.1.xsd', or version 1.1, for short. Schema versions with the same major version number are guaranteed backwardly compatible, so, for instance, the version 1.1 schema can safely be used to validate version 1.0 documents. Note that, if you are looking to view xsd:include'd schemas using a browser, the URL to use is the path of the schema you are looking at (everything up to, but not including, the actual schema filename) + the schemaLocation attribute of the xsd:include. In the current case, this gives: 'http://services.natureserve.org/docs/schemas/biodiversityDataFlow/1/' + '1/BiodiversityDataFlow_v1.1.xsd' or: http://services.natureserve.org/docs/schemas/biodiversityDataFlow/1/1/BiodiversityDataFlow_v1.1.xsd