Halo Infinite audio drops
From Halopedia, the Halo wiki
During the February 2021 edition of the Inside Infinite blog, a hidden audio drop was included as a link for fans to find. The audio file details a conversation between Dr. Halsey, John-117 and Roland concerning the actions of Cortana and the rise of the Created, following the events of Halo 5: Guardians.
The audio file was linked to as part of a comment by 343 Industries' World Design Lead John Mulkey, mentioning that Installation 07 has "stories to be found" - indicating that this audio or similar pieces may be a collectibles system akin to the Audio logs of Halo 5 or Sadie's Story in Halo 3: ODST.
Similar audio was released as a hidden part of the Discover Hope trailer.
The audio begins, and typing on a keyboard can be heard.
Heavy footsteps can be heard getting closer.