Mass Effect 3's Leviathan DLC will add extra dialogue to the ending according to code pulled from the recently released Extended Cut DLC. Eurogamer spotted chatter on this (very spoilery) Bioware forum thread , which contains a link to this pastebin with new script lines referring to the upcoming DLC pack.
And that's as much as I'll say about that in case your eyes betray you skip a few sentences and start automatically absorbing spoilers at a rate of three twists per minute. Like mercury sinking into skin, once that knowledge is in there, it ain't coming out. However, you might be interested in the other files found in recent Mass Effect 3 updates, which subtly hint at some DLC related to Mass Effect's wretched hive of scum and villainy, Omega. Mass Effect 3 spoilers lie ahead.
During Mass Effect 3, Omega is occupied by Cerberus, but there's some Aria dialogue hidden in the game files that hint at a mission to retake the space station from the Illusive Man. Some new weapon mod upgrades are contained within the recent Firefight DLC pack, with six "Omg" maps listed, including one called "OmgHub," suggesting that we could be revisiting Omega in a future chunk of DLC.
That'll be a bit further off, though, and there's still no release date for Leviathan. Here's the Leviathan trailer via IGN , snipped from the EA Summer Showcase.