Transient Rack Modules
Large sound collections on-the-fly.
Rack modules Synfire happens to find on an Audio Engine that are not part of any particular arrangement, are transient (temporary). The sounds of transient modules however are available for use, like any other module's.
If you open a project in your DAW that was saved with Drones not belonging to any particular arrangement, these Drones will appear on your racks as transient modules. Provided these modules have once been saved as a preset, Synfire will automatically detect the Device Description to use when it appears online again.
When the DAW goes offline (the project is closed), the Transient Drones simply disappear from all racks again.