This is a test app built to test the deployment instructions for GitHub pages.
The test deployment was successful, including re-deploying with changes.
To deploy this app I followed the instructions on this video exactly:
https://www.youtube.com/watch?v=7wzuievFjrk by Debugger Media
The biggest takeaway here was not to touch the Github pages page or launch a deploy manually, but to do it in the CLI as in the video.
To redeploy with changes, running npm run deploy and waiting a couple of minutes works.