This is part of the Fake.BuildServer.AppVeyor module.
native support for AppVeyor specific APIs. The general documentation on how to use CI server integration can be found here. This module does not provide any special APIs please use FAKE APIs and they should integrate into this CI server. If some integration is not working as expected or you have features you would like to use directly please open an issue.
AppVeyor environment variables as described
AppVeyor parameters for update build as described