How to add a button to the panel in the list of infoblock elements?

Question

1C-Bitrix

the essence of the task is to add a button for unloading elements to the panel, which is in the list of elements of the infoblock. I wrote the functionality of the button, but how to place it in the panel (next to the rest of the control buttons) is not clear. I tried to add a button in the text result_modifier.php , but it is not displayed (maybe I did something wrong). What is the best way to proceed in this case?