Is pytorch's subtree 'torch/lib/TH' (pre v0.4.x) independent of the original torch TH repository?

I’m playing with old pytorch versions (before v0.4.x) nowadays. It seems like the original torch repository(https://github.com/torch/TH) hasn’t changed for 3 years, but pytorch’s ‘torch/lib/TH’ directory keeps changing.

Even from the beginning of this subtree(https://github.com/pytorch/pytorch/commit/c3f0c1e2e0381c0927b5fef8719960922b182581), I failed to find out what commit of the original TH repository is this subtree pointing to.

git-subtree-dir: torch/lib/TH
git-subtree-mainline: d7504b1
git-subtree-split: 9f108b5 . << I thought this commit should lead me to the original TH repository. But it’s pointing to a pytorch commit…

My guess is that ‘torch/lib/TH’ is now independent of the original TH repository and ‘torch/lib/TH’ is not really independent of pytorch in a sense that some specializations for pytorch has been done as opposed to what the documentation says. Is it right?