Time for me to sound crazy. I won't comment on the debunking. I am sure there's a logical explanation but I am not qualified to make decisions using the evidence I have (which is often true of people on both sides of the discussion, here, generally). I terms of "are they here", it isn't totally crazy to imagine an AI that can self replicate it's frame, and use this ability to explore the galaxy. When it finds places…
The craft being observed (all over the world) are from a breakaway civilization. They were developed within the last century, possibly with the aid of extraterrestrials via an archeological finding or even direct communication, but that's an unknown for me.
I do however know the names of most of these craft, and once you know the names there is more detailed information out there including close-up images. They are quite cool, but to my knowledge are entirely terrestrial. The USG may try an alien false flag as a ploy for funding in the near future.