Vandal Savage mentions to Superman the name "Ray Palmer", and begs Superman to stop his past self from stealing a "white dwarf-powered" device from Palmer. Ray Palmer is the name of the DC super-hero "The Atom" and the source of his shrinking super power comes from a white dwarf star that he possesses.
Among the items in the trunk of the car Superman finds are the Lightning energy bars Flash advertised in "Eclipsed".
It's not clear how far in the future Superman traveled. At one point, Vandal Savage says he's had 30,000 years to reconsider his actions. However, there's no indication that they're exactly 30,000 years from Superman's "death" and could be much farther in the future.
In Action Comics #300, Superman is trapped in earths future where, under a now red sun, he has no powers. This story may have influenced Dwayne McDuffie.