docs/data/reusables/codespaces/about-features.md

Features are self-contained units of installation code and dev container configuration, designed to work across a wide range of base container images. You can use features to quickly add tools, runtimes, or libraries to your codespace image. For more information, see the available features and features specification on the Development Containers website.

You can add features to a devcontainer.json file from {% data variables.product.prodname_vscode_shortname %} or from your repository on {% data variables.product.prodname_dotcom_the_website %}.