# Documentation & Resources
## MailExtension Development
A few helpful resources relevant for developing add-ons for Thunderbird.
| | Description |
| ---------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [AI skill file](https://github.com/thunderbird/webext-support/tree/master/ai) | Teach your AI assistant how to code Thunderbird WebExtensions. |
| [addons.thunderbird.net](https://addons.thunderbird.net) | The official Thunderbird add-on repository. |
| [List of Thunderbird app versions](https://addons.thunderbird.net/pages/appversions/) | A list of all supported values, which can be used as `strict_min_version` and `strict_max_version` values in add-on manifest files. |
| [Debugging Guide](https://extensionworkshop.com/documentation/develop/debugging/) | A guide from the extension workshop with the most recent information on debugging add-ons. It is written for Mozilla Firefox but applies for Thunderbird as well. |
| [Supercharge your Thunderbird extension debugging](https://arndissler.net/supercharge-your-thunderbird-extension-debugging/) | A guide how to use Visual Studio Code to debug Thunderbird extension. |
| WebExtension API Documentation for Thunderbird | Documentation of all WebExtension APIs supported by Thunderbird.
|
| [Thunderbird WebExtension Examples](https://github.com/thunderbird/webext-examples) | A collection of explanatory WebExtension examples for Thunderbird. |
| [Firefox WebExtension Examples](https://github.com/mdn/webextensions-examples) | A collection of WebExtension examples for Firefox and other browsers. They probably won’t work directly in Thunderbird, but they may provide hints on how to use some of the WebExtension APIs that Thunderbird inherited from Firefox. |
| [Thunderbird WebExtension Support Repository](https://github.com/thunderbird/webext-support) | The WebExtension support repository provides additional tools, scripts, custom elements, Experiment APIs and other resources, to simplify the development of WebExtensions for Thunderbird. |
| [Bugzilla](https://bugzilla.mozilla.org) | Central bug tracking for Mozilla projects. Some useful pages related to Thunderbird:
|
| [Mozilla Developer Documentation (MDN)](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions) | The main documentation for Mozilla developers. As Thunderbird is based on the Mozilla platform, some Mozilla documentation is valid for Thunderbird as well. Useful MDN pages on WebExtension are:
|
## Experiment Development
Useful resources for converting legacy extensions or for creating Experiments.
| | Description |
| -------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [Searchfox](https://searchfox.org/) | An online viewer to search the Firefox code base ([*mozilla-central*](https://searchfox.org/mozilla-central/source/)) and the Thunderbird code base ([*comm-central*](https://searchfox.org/comm-central/source/)). |
| [Firefox Source Tree documentation](https://firefox-source-docs.mozilla.org/) | The current Firefox code documentation, which might be needed when converting legacy extensions. |
| [Thunderbird Source Tree documentation](https://developer.thunderbird.net/thunderbird-development/codebase-overview) | The current Thunderbird code documentation, in addition to comments in [idl files on comm-central](https://searchfox.org/comm-central/search?q=\&path=*.idl). This is still work in progress. |
| [Archived XUL and XPCOM Documentation](https://udn.realityripple.com/docs/Mozilla) | The archived Mozilla documentation includes information about internal components and functions used by legacy extensions. Please be aware, that those pages are not maintained and are potentially outdated. Some useful direct links:
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