Settings Add-ons, extensions, and themes Enhance product functionality with add-ons, extensions, and themes. All All articles and threads Import and export settings Add-ons, extensions, and themes In English Filelink for Large Attachments Permission request messages for Thunderbird extensions Thunderbird add-ons - frequently asked questions Installing an Add-on in Thunderbird How to Customize the New Mail Sound How to Install and Use another Language in the Dictionary on Thunderbird Install themes to change the look of Thunderbird Unified Toolbar Certificates Add-Ons FAQ Open Search Add Search Engine to Open Search How can I digitally sign and encrypt emails? Installing and Using another Language in the Dictionary How to Customize Toolbars Unable to install add-ons (extensions or themes) in Thunderbird Unable to uninstall add-ons (extensions or themes) userChrome.css and .js and userContent are unsupported