When on, the following episode information will be synced between devices: current play position, "played" status, and whether the episode is "local" or deleted. Similar to podcast syncing, if an episode is deleted or downloaded, that episode will be deleted or downloaded on all other devices1.
Note: episode media files are not synchronized.
If an episode is downloaded on one device but that episode has not yet been "discovered" by other devices through a feed refresh, it will not auto-download on those devices. In that case, it will be downloaded on the next feed refresh.