Most of the "Export" menu's entries are self-explaining. Therefore, only some important commands are explained.
Export Central...
Manage your → export resources and files.
Update Time Line Cache
Reads all available simulation files, e.g. during or after → command line simulations. An orange bar in the → timeline represents the loaded files.
Alternative Scene Paths...
Choose, which other drives you want to use when the main drive is full. See → here for more information.
Selected nodes as XML
Exports selected nodes to a XML file for an economic exchange of project files. Simulation data is not included. Reload the file with Import > Nodes from XML...
Scene as XML
Exports all scene nodes to a XML file for an economic exchange of project files. Simulation data is not included. Reload the file with Import > Nodes from XML...