I mean Unidentified Aerial Phenomena.

I mean Unidentified Aerospace-Undersea Phenomena. 

This latest moniker for the thing we all still think of as UFOs is the US government's way of addressing how these alleged appearances, which began entering mainstream attention in 2017, are said to be able to transition seamlessly from traveling through the air to moving underwater in what's been labeled "cross-domain transmedium" movement. Because branches of the US war machine are roughly broken up into forces specializing in air, sea, land and space operations, the notion that these things move between those domains gets special attention.

UFO enthusiasts are largely focusing on a part of the addendum which oddly stipulates that the government's newly named Unidentified Aerospace-Undersea Phenomena Joint Program Office shall not be looking into objects "that are positively identified as man-made," because of the obvious implications of that phrase. This is understandable; if you've got a government office that's responsible for investigating unidentified phenomena, you can just say it won't be looking into phenomena that are "positively identified". You wouldn't have to add "identified as man-made" unless you had a specific reason for doing so.