I modified the ticket subject header to give the tickets a uniform structure. We use a list of elements for our machine models. The machine model that a ticket is about should be placed in square brackets at the beginning of the subject.

I successfully modified the code under include in class.ticket.php after line 500.
function getSubject() {
return (string) $this->getAnswer('subject');
}
change to
public function getSubject() {
$subject = (string) $this->getAnswer('subject');
$equipment = (string) $this->getAnswer('equipment-model'); // model variable
return $equipment ? "[{$equipment}] {$subject}" : $subject;
This change shows the relevant model in the subject header between square brackets.
However, this is only displayed in the opened ticket.
I cannot find where the change must be made to display it in the ticket queue overview?