Now that Orion Platform 2020.2 and its modules are generally available (see this announcement for details), the SWIS Schema documentation has also been updated. You can now see documentation of the API for the past four releases (2018.4, 2019.2, 2019.4, and 2020.2). Select the version that matches your environment and read the docs here: http://solarwinds.github.io/OrionSDK/