When I plug in a key with Librekeys firmware, I have this popup:
However, with the current setup I get a certificate warning about *.github.com certificate being encountered, as DNS points to GitHub, get redirected to librekeys.github.io if I ignore the warning.

I'm not sure about the intention, but I'd recommend to slightly reorganize this page, to have a landing page, and move the current documentation welcome page to a sub-page, and to configure GitHub Pages with a custom domain of www.librekeys.org and/or librekeys.org, to make this experience communicating trustworthiness.
https://docs.github.com/en/pages/getting-started-with-github-pages/securing-your-github-pages-site-with-https
When I plug in a key with Librekeys firmware, I have this popup:
However, with the current setup I get a certificate warning about *.github.com certificate being encountered, as DNS points to GitHub, get redirected to librekeys.github.io if I ignore the warning.

I'm not sure about the intention, but I'd recommend to slightly reorganize this page, to have a landing page, and move the current documentation welcome page to a sub-page, and to configure GitHub Pages with a custom domain of www.librekeys.org and/or librekeys.org, to make this experience communicating trustworthiness.
https://docs.github.com/en/pages/getting-started-with-github-pages/securing-your-github-pages-site-with-https