Library (Earth-2042)

The Library, known to the Covenant as the Repository of Fate, is the name given to a structure present on the installations of the Halo Array. The Libraries are vast archive complexes and research facilities, housing the collated genetic information of numerous sentient species indexed by the Lifeworkers during the Conservation Measure, an effort to re-seed life in the the galaxy following the activation of the Halo Array. The structure also houses the activation index, the object used to activate the Halo ring and simultaneously initiate the repopulation process of the species archived in the Library.

Source

 * https://www.halopedia.org/Library