Tim Hunt

Short answer: quite a lot (because you have the stuff belonging to mod_quiz, and the stuff belonging to core_question, but it is quite logical once you understand it.)

The quickest way to find this out is to start reading code at https://github.com/moodle/moodle/blob/269a8a8a1b3965e95e713ccc93ad1b7eb0d0e249/mod/quiz/locallib.php#L2038.

Or, for spoilers, this DB query joins most of the affected tables: https://docs.moodle.org/dev/Overview_of_the_Moodle_question_engine#Detailed_data_about_an_attempt

Please don't cross-post. I replied to this in the General developer forum.

You do not want stop the timer display in the browser - that is just a display for the user.

The real enforcements of time limits are on the server-side - so I think what you acutally want to do is to ensure that the start time of the student's quiz attempt is the time that they acutally could start working on their attempt, and not the time when they started connecting ot the proctoring system.

So, acutally, why set up proctoring after the attempt has started. Why not use the 'pre-flight check' hooks in the rule, to get the connection to proctoring working before the student starts their quiz attempt? That way, there is no chance of the student seeing the questions before proctoring has begun.

For comparison, grades overridden in the gradebook to show to students in the quiz - but not in the quiz reports for teachers - I think there is a really old enhancement request about fixing the quiz reports.

Can you set Debugging to 'Developer' level, and then show us the full error message. (You probably want to set the debugging level back afterwards.)