Haven't seen this posted here anywhere so thought I would go ahead and make everyone aware, this was posted by GlassWalls at mightnight just last night. This was also posted by GlassWalls in a thread questioning the time this maintenance should begin at. Not sure if this means regular maintenance Wednesday night either, but this much here has been confirmed for tonight. Guessing it has to do with the 1.5 Core client update to Home this week ;D
By those times it sounds pretty much like the average weekly update times, but with no early blog post we can't be sure if it is an early content update... I think it's more likely what Carla said in the chat earlier and it's in preparation for 1.5 coming later in the week
Guess I missed that convo, but yeah it sounds to me they're simply preparing to upgrade the core client, rather than packing it into one single update. Possibly to avoid taking so long Wednesday night/Thursday morning, is my best guess.