Set a favicon on GitHub pages when using a README

I have Pages enabled for my GitHub repository. The data is coming from my README.md file, as I have no index.html in the repository. This is what I want. However, I'm trying to get a favicon for my page, and I can't figure it out. All the guides online describe using <link rel> with a favicon, as one would in HTML, but I don't see anything for when automatically feeding the page data from the repository's README.

I'm not sure what I can provide as a minimal replicable example. Below are the source and theme settings from the repository's Pages settings.

Thanks.

Unless Github adds this feature, the only way you can do it is by editing the HTML files. You can do it by adding to your repository the theme layout file and editing it.

Someone had the same issue and described the solve it here: https://github.com/pages-themes/cayman/issues/93