It's not really new info, but it's worth restating. In December's update notes, there was the following line:
"New Meeble Burrows expeditions were also scheduled to be introduced, but have been postponed for approximately one month so that they can undergo more thorough testing."
So, assuming no further delay, I'd expect these to be added in a spontaneous maintenance either this week or next. This refers to the three ranks of Batallia Downs expeditions that are referenced in the dats by titles for defeating certain NMs and the key items associated with their defeat (sounds like the system will be the same as in Sauromugue except there will just be three ranks - Adjunct, Instructor, and Researcher). The reward items are all in the dats already and I previously compiled them in a table here under "Batallia Downs" --
https://www.bg-wiki.com/bg/Meeble_Burrows/Rewards
Of course it's just assumed for now that that's where those items will be from, but there's really nothing else they could be from.