new effect stack menu item - "create region" - use?

So I just noticed that in ver 0.9.3 there is a new menu item available from the effects in the effect stack - "create region" This is in addition to the Reset Effect, Create Group and Save Effect options that are part of 0.9.2

See screen shot

So what does "create region" do ? - so I can add it to the manual. If you select it you get a file dialog asking you to choose a file. But I dunno what sort of file it takes as input and what it to do with it.