TL;DR: When one file has staged and unstaged changes, a commit will commit both versions, with the most recent changes to the file.

How do you unstaged a commit?

To unstage commits on Git, use the “git reset” command with the “–soft” option and specify the commit hash. Alternatively, if you want to unstage your last commit, you can the “HEAD” notation in order to revert it easily. Using the “–soft” argument, changes are kept in your working directory and index.

Are unstaged changes committed?

So "unstaged changes" aren't linked to GitHub, but are local modifications on your local repo, which you haven't yet added to the index ("staged"), for a future commit.