Is there a git-like file system?

Is there a git-like file system?

Git stores content uniquely in its repo based on the calculated hash of
any file. Thus, if my directory has two copies of the same file somewhere
inside it, git will only actually store it once.
I am wondering if this same concept has been implemented at the
operating-system level as some kind of file system?
One of the sweet spots in Unix systems are symlinks because they
effectively allow content to exist in multiple places at the same time
without the added byte cost of actually storing the same content multiple
times. If a file system was smart enough to do this automatically, this
would seem to pose a good possible solution for "dll hell" issues.
Ruby enthusiasts share libraries by publishing them as rubygems. Still,
this effort to share gems resulted in deployment nightmares that lead to
the Vendor Everything concept of copying all dependencies into local
folders to avoid such nightmares. I am wondering secondly if such a file
system does exist, wouldn't it be a good complement to the "Vendor
Everything" approach? (This question is a tangent to the first and primary
question.)