Codespaces es un servicio de GH que provee el mismo entorno de desarrollo que VSCode en la nube de GH.
Si quieres personalizar tu Codespace, puedes leer Personalizing GitHub Codespaces for your account.Puedes personalizar GitHub Codespaces usando un repositorio dotfiles en GitHub o usando Settings Sync.
To speed up codespace creation, you can configure your project to prebuild codespaces for specific branches in specific regions. You create and configure prebuilds in your repository’s settings.
See the documentation at codespaces/prebuilding-your-codespaces.
A prebuild assembles the main components of a codespace for a particular combination of repository, branch, and devcontainer.json configuration file. It provides a quick way to create a new codespace. For complex and/or large repositories in particular, you can create a new codespace more quickly by using a prebuild. Whenever you push changes to your repository, GitHub Codespaces uses GitHub Actions to automatically update your prebuilds.