Since Jupiter X 1.21.0 the Raven is merged with Jupiter X Core plugin. All the features available in the Raven are available in the Jupiter X Core plugin now and you no longer need it. Just update the Jupiter X theme and Jupiter X Core plugin to the latest version.
Raven plugin is developed by Artbees team specially for Jupiter X theme and Elementor.
It’s required to activate it so you can use additional elements in Elementor page builder.
There are 22 custom elements added to Raven and all of them are described in the Raven category. Also, it adds the custom header and footer features to Elementor (basic edition). For more information about Raven plugin, please check this article.
Note: Please make sure the plugin server requirements are provided on your web host first. You can check the Jupiter X server requirements here. Also, read this article to understand why you should keep your active plugins at a minimum.