Sourcegraph for Firefox is an open-source browser extension designed to improve code navigation and intelligence across various code hosting platforms such as GitHub, GitLab, Bitbucket Server, and Phabricator. Key features include hover tooltips that provide documentation and type information, the ability to go to definitions, and finding references with ease. It supports over 20 programming languages, making it a versatile tool for developers working on both public and private repositories.

The extension seamlessly integrates with third-party services like Codecov and offers a convenient browser shortcut for quick searches. While it works out of the box with GitHub, additional permissions are required for other hosts. Users can set up a private Sourcegraph instance for private repositories, ensuring secure access to their code. Comprehensive documentation is available for installation and integration, making it straightforward for developers to enhance their coding experience.