Remote app/arch/branch mismatch with real remote: "No such ref" error

When using GitHub and Netlify to deploy a Flatpak repository, I have on that remote the path: refs/heads/app/${APPLICATION_NAME}/x86_64/master, but the flatpakref that I’m attempting to use with GNOME Software is resulting in the error containing the path: refs/heads/app/${APPLICATION_NAME}/x86_64/main.

There is a mismatch between master branch and main branch in the Flatpak repo. How is this name chosen, and how can I ensure that the branch is chosen correctly?