Aside from http://forum.synology.com/enu/viewtopic.php?f=117&t=10065&p=46607&hilit=%40eaDir#p46607, site search doesn't reveal much information on the hidden directories named "@eadir". That other thread is five years old, so I have some questions.
1) Are those @eadir directories created only in directories where file indexing has been enabled?
2) Can a @eadir be deleted without any side effects, except perhaps when doing a File Station search?
3) Is there some way to delete all the @eadir's at once?
It's particularly annoying to see all those @eadir's on my Android phone when I'm syncing directories with BitTorrent Sync. So I'd like to know if it's simply a choice between file indexing and neater file listings.