Table of contents About Thunderbird The Basics Getting Started Building Thunderbird Windows Build Prerequisites Linux Build Prerequisites macOS Build Prerequisites Artifact Builds Codebase Overview Examples Hello World Contributing Fixing a Bug Using Mercurial Queues Using Mercurial Bookmarks Lint and Format Code Try Server Landing a Patch Testing Running Tests Adding Tests Writing Mochitest Tests Planning 78+ Roadmap Add-ons About Add-ons Updating Legacy Extensions for Thunderbird 68 Convert Overlay Extension to MailExtension with legacy support Convert Bootstrapped Extension to MailExtension with legacy support Changes in Thunderbird 61-68 Updating Legacy Extensions for Thunderbird 78 Changes in Thunderbird 69-70 Tips and Tricks for Add-on Development Add-on Examples Hello World MailExtension WebExtension Themes More Examples Add-on Resources MailExtensions APIs ThunderKdB: Extension Developer Resources Thunderstorm Repo addons.thunderbird.net