Insider Fast Track Office
If you see all the other updates listed it is replaces 2 of the updates that have been causing a lot of members problems
One being the 9th Feb one.
Also they have marked it as critical update.
I have seen some improvement over all
Faster start up
Also why they are doing manual download is because a lot of member have been having trouble with W U by some updates installing 4, 5 times.
If the OP does a backup before installing this latest one if it does not help then he can always roll back