It is this (or the equivalent if I have the q type incorrect)
https://github.com/moodle/moodle/blob/master/question/type/multichoice/edit_multichoice_form.php
Generally it is a bad idea to modify any core code as it will get overwritten on the next upgrade. What are you trying to do?
https://github.com/moodle/moodle/blob/master/question/type/multichoice/edit_multichoice_form.php
Generally it is a bad idea to modify any core code as it will get overwritten on the next upgrade. What are you trying to do?