Interestingly, it's not GE Aviation (the GE division who make engines) but GE Additive, a division of GE who specialise in Additive manufacturing (aka 3D printing) metal parts.
So it's going to have 3d printed rotors and probally other , which is super cool.
GE Additive have previously made 3d printed turbine parts for GE Aviation[1], so they do have some experience. Also, this appears to be Kratos' second jet engine [2]
Turbine blades are the bits that whizz around really fast and are subject to extremes of temperature and force. Established engine manufacturers go to interesting lengths to make turbine blades made of interesting materials like single crystal metal alloys just so that they can cope with the conditions. In a jet engine, a small increase in working temperature gives a significant improvement in efficiency and performance. I can't see how 3D-printed turbine blades could possibly be a good idea.
It doesn’t look like they printed the rotors. It’s hard to find real concrete info but it looks like they added cavities to other parts of the engine for active cooling and/or increased strength to weight, which is more of a well explored topic (I remember watching a rocket engine test in Mojave with a hollow cryocooled aluminum nozzle in the late 2000s).
The rotors are still made using those fancy 5-axis CNCs - I think either Boeing or GE still have a shop in LA that makes them.