An example of Eclipse p2 Composite update site built during the Maven/Tycho build and published it on GitHub Pages.
This is described in this post:
http://www.lorenzobettini.it/2021/03/publishing-an-eclipse-p2-composite-repository-on-github-pages/
The update site hosted here can be consumed by Eclipse by using this URL
https://lorenzobettini.github.io/p2composite-github-pages-example-updates/
The project with the features and bundles for this update site can be found on this other GitHub repository
https://github.com/LorenzoBettini/p2composite-github-pages-example