Sextant is a free Chrome add-on designed to enrich GitHub repository pages by providing an instant overview of code metrics. Upon loading a repository, users can see a dedicated 'Lines of Code' panel that displays the total source lines of code (SLOC), file count, and a breakdown of the top ten programming languages used in the repository. This feature operates seamlessly without requiring any additional clicks, making it efficient for developers to gauge project size and complexity at a glance.

The add-on utilizes three data sources to ensure accurate and comprehensive data retrieval. For public repositories under 500 MB, it employs a free public API from codetabs.com. For larger or private repositories, it relies on a dedicated backend that utilizes the scc tool for precise SLOC counts. Additionally, it offers a fallback estimate from GitHub's languages API if other sources are unavailable. Users can connect their GitHub accounts securely, ensuring privacy and data protection throughout the process.