Moon is a Grimoire card from the original Destiny (Destiny 1), found under Places → Moon. Grimoire cards held most of the game's lore and were read on Bungie.net and in the companion app, not in the game itself.
Card text
Earth's Moon was where we first faced the terror of the Hive, and it soon became the battlefield of a great war - one we did not win. In the years since, the Hive have ripped the Moon's surface apart, opening chasms that swarm with terrors.
Grimoire text written by Bungie, shown as it appears in the Destiny 1 game files.