Editor.copyNodes to copy the currently selected nodes to the system clipboard.
stron the system clipboard.
strto the contents of the clipboard, which contains a single unformatted text item.
An example of (1) why I want (1) is as part of a Keyboard Maestro macro put the topic of the current item of an outline on the system clipboard, switch to another application, and paste. Similarly, an example of using (2) would be a Keyboard Maestro macro that executed some steps that include copying a selection from another application, switching to Omni Outliner, and using the contents of the system clipboard to construct some text that will go in an outline item.