> Here are some completely normal and plausible [reasons]. It was worked on over weeks internally, commits referenced other internal NVIDIA software/libraries they used. It name dropped projects and code names. Maybe it was just an extremely long chain of messy commits that is improper to have on a potentially big open source repo.

... it referenced internal servers and they want to scrub that for security reasons

... it might have had secrets embedded at some point because it was a quick and dirty proof-of-concept

... it could have had swear words in the code

... it had enormous binaries checked in at one point and they don't want the repo to be huge

... they don't want you to know the names of everyone that worked on it

... it's forked off other internal work that isn't public yet

There are so many reasons that the easiest thing to do is just snapshot it and have minimal public git history. Some places I've worked make it so publicly, there's one commit per release. Did NVidia do this? Well, they didn't collapse it down to a single commit, but we have no evidence that the commits we see were the actual internal development timeline.