What does mail_event_bulk mean?

Question

1C-Bitrix

Found in documentation :

COption::SetOptionString("main", "mail_event_bulk", "20"); 
echo COption::GetOptionString("main", "mail_event_bulk", "5");

But I can not find a sane explanation of what it is and how to use it,

Answer 1

The first link in Yandex on request mail_event_bulk

parameter responsible for the number of mail events processed at a time