Updated Design: Library Sidebar (markdown)

Design:-Library-Sidebar.md

@@ -213,4 +213,12 @@ The 'import' button behaviour will depend on the current editor state:
  - in 'normal' mode, import will import the selected flow, or the node of the appropriate type.
  - if a node is being edited, the 'type' select will be restricted to the required type and clicking import will copy it over to the node edit dialog
 
-**Todo:** what is the `export to library` workflow.
+**Todo:** what is the `export to library` workflow.
+
+---
+
+# External Library API
+
+A common request is to be able to have a shared library between a team of developers. The current model works if they are sharing a node-red instance (as the current library is local to the runtime), but doesn't help where you have assets that should be shared across instances.
+
+So... what's the right way to allow other libraries to be plugged in?