In 1974 Ken Thompson sent a copy of the then-current Unix distribution to Marin Newell. Fast forward to to July 28th, 2025. In a storage closet of the Robert Ricci’s Flux Research Group at the Merrill Engineering Building Aleks Maricq a research associate found a tape labeled v4 Unix among the documents of Jay Lepreau. This could be significant, because no other version of its source code have survived. The finding was widely reported on the web and even broadcast TV. To avoid high-altitude cosmic radiation and airport scanner damage lab members Jon Duerig and Thalia Archibald undertook an 11 hour drive it to the Computer History Museum in December 2025. There it was decoded and made available using a sophisticated analog to digital pipeline. A few days later, I integrated the tape's contents in the Unix History Repository. This makes available on GitHub a repository, covering the period from Unix's inception in 1970 as a 2.5 thousand line kernel and 48 commands, to 2025 as a widely-used 41 million line system. The 2 GB repository contains about 850 thousand commits and more than eight thousand merges. Based on the repository's contents I provide details regarding the tape's contents, dating, code provenance, and the evolution of programming language adoption.