I couldn’t believe it! You can find the official announcement here.
So this is MS-DOS 1.1 & 2.0 source code. Pitty it’s not 3.x but heck, it’s a start!
Also the Word in question is 1.1a however it does seem to include the OS/2 bits which was a big surprise.
I haven’t tried to build any of it, as I just got up but I know what I’ll be doing today!