According to a Daily Mirror publication, a mention of a possible alien base on the Moon was found in another package of declassified NASA documents.
Among the 72 new files published by US authorities on the Pentagon website on Friday, June 12, an audio recording of a secret NASA meeting was found. This meeting took place after the completion of the Apollo 16 mission in 1972. During this mission, American astronauts landed on the surface of Earth's satellite for the fifth time and conducted a series of scientific experiments.
During the meeting, NASA employees discussed various scientific issues, including laser measurements and lunar gravity. The conversation touched upon a "huge hole" near the Van de Graaff crater on the far side of the Moon. One of the meeting participants made the following remark: "This could be an alien base or something of that nature. In any case, on the next slide, the visible side of the Moon is already there."
The publication notes that this remark was made quite casually, after which the scientists moved on to jokes about the "huge hole" on the far side of the satellite.