Gist for my tutorial: Building a Gutenberg sidebar plugin Part 3: Registering with the block editor. https://vanaf1979.nl/building-a-gutenberg-sidebar-plugin-part-3-registering-with-the-block-editor/

metatags-sidebar-menu.js

/**
 * Sidebar component voor the gutenberg editor.
 */
class Sidebar extends React.Component {
    
    ...

    render() {

        return (
            <Fragment>

                <PluginSidebarMoreMenuItem target="metatags-sidebar" icon='editor-customchar'>

                    {__("MetaTags", "metatags")}

                </PluginSidebarMoreMenuItem>

            </Fragment>
        )

    }

}


export default Sidebar