Пример кода использования внутренних блоков в WordPress с ES5

( function ( blocks, element, blockEditor ) {
    var el = element.createElement;
    var InnerBlocks = blockEditor.InnerBlocks;
    var useBlockProps = blockEditor.useBlockProps;
 
    blocks.registerBlockType( 'softhunt/inner-example', {
        title: 'Inner Blocks',
        category: 'design',
 
        edit: function () {
            var blockProps = useBlockProps();
 
            return el( 'div', blockProps, el( InnerBlocks ) );
        },
 
        save: function () {
            var blockProps = useBlockProps.save();
 
            return el( 'div', blockProps, el( InnerBlocks.Content ) );
        },
    } );
} )( window.wp.blocks, window.wp.element, window.wp.blockEditor );
Outrageous Ostrich