Sodium chloride, or table
salt, spotted on its surface could mean that its buried ocean has a
composition similar to those on Earth and is therefore good for
They found signs of sodium chloride turning the surface yellow as it was bombarded with radiation from space. The strongest of these signals came from Tara Regio, a "chaos region" thought to be shaped by water seeping up from the subsurface ocean.
That indicates that the salt could be coming from within Europa, hinting at the ocean's chemical composition.
That's a good sign, in terms of habitability.
Earth's oceans are the only ones in the universe that we know to be habitable.
The subsurface ocean of Saturn's moon Enceladus has many of the necessary ingredients for life, such as complex organic molecules, and is also full of sodium chloride.