The content of this repository is a source code for Gatsby.js + Netlify CMS + Firebase article, where I explain how to install Netlify CMS to an existing Gatsby website (as example I use clean Gatsby.js project without templates), host it at Firebase and implement continuous delivery with GitHub Actions.
You can also use this repo as yet another Gatsby + Netlify CMS blog starter template. But I would recommend to use the one from official docs: https://github.com/netlify-templates/gatsby-starter-netlify-cms