Add Extension:WikiEditor toolbar integration

https://www.mediawiki.org/wiki/Topic:Vordfbar0y535akp

var customizeToolbar = function () {
  $('#wpTextbox1').wikiEditor('addToToolbar', {
      section: 'advanced',
      group: 'insert',
      tools: {
        "Map": {
          label: 'Insert map',
          type: 'button',
          icon: '//upload.wikimedia.org/wikipedia/commons/b/b4/OOjs_UI_icon_map-ltr.svg',
          action: {
            type: 'encapsulate',
            options: {
              pre: '{{#display_map:',
              peri: "Example street 1, Berlin~'''Heading'''~Short description; optional: 2nd marker",
              post: '|fullscreen=on}}'
            }
          }
        }
      }
    });
};
    
    /* Check if view is in edit mode and that the required modules are available. Then, customize the toolbar … */
    if ( [ 'edit', 'submit' ].indexOf( mw.config.get( 'wgAction' ) ) !== -1 ) {
    mw.loader.using( 'user.options' ).then( function () {
    if ( mw.user.options.get( 'usebetatoolbar' ) == 1 ) {
      $.when(
        mw.loader.using( 'ext.wikiEditor' ), $.ready
      ).then( customizeToolbar );
    }
  } );
}

https://www.mediawiki.org/wiki/Extension:WikiEditor

Read the linked MediaWiki topic and Extension:WikiEditor documentation first, then locate the Maps extension's client-side integration entry point. Compare the requested snippet with the extension structure and verify the toolbar appears in edit or submit mode when the beta toolbar is enabled, with the map insertion action available.