The gas giant Endor is known to have 9 moons, and basing on the colour shown on the visual dictionary for Rise of Skywalker, I can surely say the moon that appeared in the background is either Vix or Gouuls.

[![enter image description here][1]][1]

[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/i4hKW.png
  [2]: https://i.sstatic.net/RxFD0.jpg