The functionality of MarbleCLAY can be extended by writing plugins.
Plugins can be written in Delphi/C++. See the MarbleSDK documentation for details. MarbleSDK is distributed on the author's page.
script
Scripts are implemented in plugins.
Currently v1beta does not support scripts, but v2 supports Lua scripts.
Since the script specification depends on the specification of the plugin API, the document is not maintained at this time.