This extension is deprecated! If you want an extension for saving and restoring internal plugin states, look at this instead.
This extension defines a way to save and restore the internal state of an LV2 plugin instance. The internal state does not include input port values, which are visible to the host, but rather things that the host has no way of knowing, such as loaded sample buffers that have been modified using GUI commands, or internal variables that have been updated and modified as a reaction to the input streams.
The details are in this header.