What is the name of the planet where the second Death Star is built?

The story behind the answer

The second Death Star was assembled in orbit around the forest moon, protected by a planetary shield generated from a bunker on the surface. A Rebel commando team sabotaged that generator, letting the fleet strike the unfinished battle station—an operation aided by the native Ewoks and culminating in the Emperor’s downfall.

Don’t confuse this with Yavin 4, which hosted the Rebel base targeted by the first Death Star; Sullust, an industrial world used as a Rebel staging point before the Endor offensive; or Kashyyyk, the Wookiee homeworld prominent in the Clone Wars. The pivotal “Battle of Endor” marks the turning point of the Galactic Civil War.