Just a little AI upscaling with some manual touch-up to a few still frames. AI upscaling is pretty amazing but it's still not perfect. You can see the little lines and patterns where is stitches the details together, but it's getting better all the time. Clearly it didn't interpret Jadzia's spots correctly, though!
An actual remaster wouldn't require any AI upscaling because the original film stock has all the detail. This is just for fun.
