ModifyButtonBarEvent 

Example 

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Backend\EventListener;

use TYPO3\CMS\Backend\Template\Components\ModifyButtonBarEvent;
use TYPO3\CMS\Core\Attribute\AsEventListener;

#[AsEventListener(
    identifier: 'my-extension/backend/modify-button-bar',
)]
final readonly class MyEventListener
{
    public function __invoke(ModifyButtonBarEvent $event): void
    {
        // Do your magic here
    }
}

API 

class ModifyButtonBarEvent

Fully qualified name

\TYPO3\CMS\Backend\Template\Components\ModifyButtonBarEvent

PSR-14 event that allows listeners to modify the buttons in the backend module document header button bar. This event is dispatched after all buttons have been added to the button bar, but before they are rendered.

Use cases: - Add custom buttons to existing modules - Remove or hide buttons based on conditions - Modify button properties (labels, icons, etc.) - Reorder buttons

Example event listener:

use TYPO3\CMS\Backend\Template\Components\ModifyButtonBarEvent;
use TYPO3\CMS\Backend\Template\Components\ButtonBar;
use TYPO3\CMS\Backend\Template\Components\ComponentFactory;
use TYPO3\CMS\Core\Attribute\AsEventListener;

final class MyButtonBarListener
{
    public function __construct(
        protected readonly ComponentFactory $componentFactory,
    ) }

    #[AsEventListener]
    public function __invoke(ModifyButtonBarEvent $event): void
    {
        $buttons = $event->getButtons();
        $buttonBar = $event->getButtonBar();

        $myButton = $this->componentFactory->createLinkButton()
            ->setHref('/my-action')
            ->setTitle('My Action')
            ->setIcon($iconFactory->getIcon('actions-heart'));

        $buttons[ButtonBar::BUTTON_POSITION_RIGHT][1][] = clone $myButton;

        $event->setButtons($buttons);
    }
}

Copied!

getButtons ( )

Returns

Buttons

setButtons ( array $buttons)

param $buttons

the buttons

getButtonBar ( )

Returns

TYPO3CMSBackendTemplateComponentsButtonBar

getRequest ( )

Returns

PsrHttpMessageServerRequestInterface