Supported Manifest Keys
Descriptions of all manifest keys supported by Thunderbird.
Several manifest keys in the following table are common to Thunderbird and Firefox and link to MDN description pages. Please be aware, that MDN is dedicated to browsers and of course to Firefox. Some information listed on MDN may not apply to Thunderbird.
Manifest Key
Description
Contains keys that are specific to a particular host application. Information for Thunderbird are stored in applications.gecko. See
Note: An alternative name for this key is browser_specific_settings.
author
Defines the extension's author. If the developer key is supplied and it contains the name property, it will override the author key. There is no way to specify multiple authors. This is a localizable property.
Use the background key to include one or more background scripts, and optionally a background page in your extension. Background scripts are loaded as soon as the extension is loaded and stay loaded until the extension is disabled or uninstalled,
A browser action is a button that your extension can add to Thunderbird's main mailTab toolbar. The button has an icon, and may optionally have a popup whose content is specified using HTML, CSS, and JavaScript.
Alternative for theapplications key.
Defines a file link provider, which can be used to upload large attachments to a server, instead of attaching them directly to the email.
commands
Use the commands API to add keyboard shortcuts that trigger actions in your extension, for example, an action to open a browser action popup.
Instructs Thunderbird to load content scripts into web page tabs and windows, whose URL matches a given pattern.
The default policy restricts the sources from which a content script can load <script> and <object> resources, and disallows potentially unsafe practices such as the use of eval(). See Default content security policy to learn more about the implications of this.
A compose action is a button that your extension can add to the toolbar of Thunderbird's message compose tabs. The button has an icon, and may optionally have a popup whose content is specified using HTML, CSS, and JavaScript.
This key must be present if the extension contains the _locales directory, and must be absent otherwise. It identifies a subdirectory of _locales, and this subdirectory will be used to find the default strings for your extension. See Internationalization.
Defines a short description of the extension, intended for display in the Add-ons Manager. This is a localizable property.
developer
Defines the name of the extension's developer and their homepage URL, intended for display in the add-on manager tab. The name and url properties, if present, will override the author and homepage_url keys, respectively. This is a localizable property.
The dictionaries key specifies the locale_code for which your extension supplies a dictionary.
URL for the extension's home page. If the developer key is supplied and it contains the url property, this will override the homepage_url key.
icons
The icons key specifies icons for your extension. Those icons will be used to represent the extension in components such as the Add-ons Manager.
This key specifies the version of manifest.json used by this extension.
Currently, this must always be 2.
A message display action is a button that your extension can add to the toolbar of Thunderbird's message display tabs. The button has an icon, and may optionally have a popup whose content is specified using HTML, CSS, and JavaScript.
name
Defines the name of the extension. This is used to identify the extension in the Add-on manager and on sites like addons.thunderbird.net.
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