Google announcing the deprecation of SWF export functionality for presentations from the Google Documents List API. They are taking this action due to the limited demand for this feature, and in order to focus engineering efforts on other aspects of the API.
Clients currently making the following request to the API are affected by this change.
We recommend clients currently using SWF exports switch to PDF exports, using the appropriate exportFormat value.
They are disabling SWF exports in the coming weeks. Clients attempting to export presentations as SWF after the exports are disabled will receive an HTTP 400 response.