2003 UB313 is an alternate name of Eris - a dwarf planet.

Eris the dwarf planet

Yes, the provisional name for Eris was 2003 UB313. A provisional name is given to an object directly after its discovery. A more permanent name is then chosen once the characteristics of the object had been calculated.

UB313 was the unofficial name for Eris the largest known dwarf planet.

Xena was used by the discovery team to denote UB313.

So yes - Xena is UB313 is Eris

Examples of minor planets include Pluto, an ex-planet, Ceres, the first asteroid to be discoverd, and 2003 UB313 or Eris.