If I find a script/notebook/project with no requirements.txt, I usually know when it was created. Being able to get the versions that were selected back then on the author's machine would be great for reproducibility.
uv pip compile --exclude-newer=2019-12-02
Even if you have all versions as of the time of the last modification to the code, you don't know if the dependency resolution happened at that point in time, or if the environment was set up years prior and never updated.
Nevertheless, this is what you are looking for: https://pypi.org/project/pypi-timemachine/
Agreed that in a perfect world I would never need this, but...