XKit.installed: helpers for dealing with installed extensions.
# XKit.installed.list()
Returns an array of installed extensions.
# XKit.installed.check(extension_id)
Returns true if extension_id is installed.
# XKit.installed.version(extension_id)
Returns the version of extension_id.
# XKit.installed.title(extension_id)
Returns the human-friendly title of extension_id.
# XKit.installed.icon(extension_id)
Returns the base64-encoded icon of extension_id.
# XKit.installed.css(extension_id)
Returns the stylesheet of extension_id.
# XKit.installed.description(extension_id)
Returns the description of extension_id.
# XKit.installed.developer(extension_id)
Returns the developer of extension_id.
XKit.installed also contains private methods reserved for XKit only that should never be used in an extension.