It is a recording of a man named Murnahan who was a private in the war. He stated that the "M-42s" otherwise known as the Fat Man, had just come in, and he was taking a peek at them with his buddy, surprised they were actually mini nuke launchers.
This holotape is located in Fort Strong on a desk by the window in the southwestern corner of the northwestern room on the ground floor.
Word came down that the Army just unloaded the first batch of the M-42's this morning. I've only seen the specs for these little beauties on paper, so Private Bertram and I snuck down to take an early look. When I heard that the eggheads were designing a man-portable nuke launcher, I thought they were nuts... but they actually got the damn thing to work. And after seeing the real thing sitting right in front of me, I think they could be just enough to tip the balance of this war in our favor. I mean, can you imagine the look on the enemy's face when we get dropped into Anchorage carrying these babies? They won't know what hit'em.
Despite being labeled as "Private Murnahan's holotape," subtitles indicate the voice is that of a "Captain Dunleavy," who is stationed at the sentinel site.