Exclude GitHub repo files from being deployed

I’ve a hunch I’m going to kick myself, but…

Is there a way to commit files to repo but exclude them from being deployed?

I’ve a very simple static site and deployment using Apps works fine.

However, I’d like to document the repo too and exclude those files from being deployed.

I can’t exclude them with .gitignore because I’d like them committed to the repo.

I tried .dockerignore but the files continue to be copied.