How can I display the images ALT tags in the media library list view?

Insert the following script in functions.php:

// Add a new column to the media library
function add_alt_text_column($columns) {
    $columns['alt_text'] = 'ALT Text';
    return $columns;
}
add_filter('manage_media_columns', 'add_alt_text_column');

// Define the content of the ALT text column
function show_alt_text_column($column_name, $post_id) {
    if ($column_name == 'alt_text') {
        $alt_text = get_post_meta($post_id, '_wp_attachment_image_alt', true);
        echo $alt_text ? esc_html($alt_text) : '<em>Kein ALT-Text</em>';
    }
}
add_action('manage_media_custom_column', 'show_alt_text_column', 10, 2);

// Optional: Make column sortable
function make_alt_text_column_sortable($columns) {
    $columns['alt_text'] = 'alt_text';
    return $columns;
}
add_filter('manage_upload_sortable_columns', 'make_alt_text_column_sortable');

// Optional: Define sorting for ALT text column
function alt_text_column_orderby($query) {
    if (!is_admin() || !$query->is_main_query()) {
        return;
    }
    
    if ('alt_text' === $query->get('orderby')) {
        $query->set('meta_key', '_wp_attachment_image_alt');
        $query->set('orderby', 'meta_value');
    }
}
add_action('pre_get_posts', 'alt_text_column_orderby');

// Optional: CSS for better display
function media_library_alt_text_column_css() {
    echo '<style>
        .column-alt_text { width: 200px; }
        .column-alt_text em { color: #666; font-style: italic; }
    </style>';
}
add_action('admin_head-upload.php', 'media_library_alt_text_column_css');