Table of contents About Thunderbird Contributing to Thunderbird Getting Started Building Thunderbird Windows Build Prerequisites Linux Build Prerequisites macOS Build Prerequisites Artifact Builds Codebase Overview Address Book Chat Core Notifications Message Styles Keyboard shortcuts Chat Core Protocols Contacts Tutorials and Examples Hello World Example Thunderbird Live Development Videos Fixing a Bug Using Mercurial Queues Using Mercurial Bookmarks Lint and Format Code Using ESLint to Format Javascript Code Try Server Landing a Patch Care and Feeding of the Tree Testing Running Tests Adding Tests Writing Mochitest Tests Planning Roadmap Backlog Add-on Development Introduction A Guide to MailExtensions Supported Manifest Keys Supported UI Elements Supported WebExtension APIs Hello World Extension Tutorial Using WebExtension APIs Using a Background Page Using Content Scripts Examples in the Sample Extensions Repository Introducing Experiments A Guide to Themes Tips and Tricks Add-on Update Guides Update for Thunderbird 68 Convert Overlay Extension to Legacy WebExtension Convert Bootstrapped Extension to Legacy WebExtension Adapt to Changes in Thunderbird 61-68 Update for Thunderbird 78 Adapt to Changes in Thunderbird 69-78 Update for Thunderbird 91 Adapt to Changes in Thunderbird 79-91 Update for Thunderbird 102 Adapt to Changes in Thunderbird 92-102 Documentation & Resources Developer Community