And rewording it like :

When you create the commit by running git commit, Git checksums each subdirectory list (in this case, just the root project directory) and stores those as tree objects in the Git repository. Git then creates a commit object that has the metadata and a pointer to the root project tree so it can re-create that snapshot when needed.

Not a typo.

And rewording it like :

When you create the commit by running git commit, Git checksums each subdirectory list (in this case, just the root project directory)

What is "subdirectory list"?

It is the list of the content of subdir. Yes, maybe expanding the phrase as "Git checksums the list of the content of each subdirectory" would be better. A pity that the only people concerned by rewordings are not native english speakers...

"Git checksums the list of the content of each subdirectory"

Doesn't seem correct to me as well. Really, the figure below this paragraph explains what is stored better then words :)

A pity that the only people concerned by rewordings are not native english speakers...

Yeah. I think we can leave this part alone until someone will write a better description.

Agreed. Just swooping in from Code Triage, but I'd suggest a complete rewriting of the paragraph if you find it that confusing (git is, so not arguing with you, but as a native English speaker it seemed alright to me, so perhaps the person who felt that might be the issue could re-write the entire paragraph segment and submit it. Otherwise, I think we should close this issue.

How about this way:

By running git commit Git checksums each directory and each file and stores those as tree and blob object types respectively in the Git repository. Git then creates a commit object type that has the metadata and a pointer to the root project tree object so it can re-create that snapshot when needed.

Sounds good to me. Ship it!... =]

The new variant is not perfectly correct IMO. On git commit Git checksums only project's subdirectories. Files are checksummed on git add.

By running git commit Git checksums

I think that dropping "When you create the commit" part makes the sentence incorrect.

tree and blob object types
commit object type

Doesn't look correct either.

Seems OK to me.