Thats what I was thinking too. Some kind of acumulator, probably some kind of presurized diaphram in there or something.
I would think you would just bleed the system normaly, they shouldn't have an impact on the bleeding procedure at all, because they should remain open (I wouldn't think they close the line off, like the Electroinc Anti-Lock brake systems do, of which only close the line in a hard ABS activation stop any-ways)