Let’s say your user or organization name on GitHub is “easy-peasy”. You want to
create a blog or something, so you create a repository named
“easy-peasy/easy-peasy.github.io”, as instructed in the GitHub Pages
documentation. Now you want to create a new repository,
“easy-peasy/lemon-squeezy” that you also want hosted on GitHub Pages, so you
gh-pages branch with an
index.html in the root. What would happen
if in “easy-peasy/easy-peasy.github.io” you created a
file, as they would have the same URL?
http://easy-peasy.github.io/lemon-squeezy would point to your “easy-peasy/lemon-squeezy” repository.