Replying to myself... Tim was right (of course). Using the $SESSION global variable only works when the student is answering the question. It no longer works when reviewing the attempt.
I will definitely have to find another solution... maybe with some help from the Moodle question type gurus.
Thanks for your suggestion, Tim, but I still have not succeeded to achieve what I need except by using the $SESSION global variable.
So for the time being my new question type, which I named "Random select answers", does work at least as a Proof of Concept. It's available on my github at https://github.com/rezeau/moodle-qtype_answersselect. I have not totally "cleaned" it of its OU references.
A sample quiz is available on my Moodle test site at: https://www.rezeau.org/moodle/mod/quiz/view.php?id=75 (login as student01, pasword Student01!) Test course 02.
Bonjour Romain,
"Je vais tenter de rajouter quelques éléments dans le code..." Surtout pas !
Cette chaîne est bien traduite et présente dans les fichiers de langue française de Moodle:
dans racinedetonsite/moodledata\lang\fr\course.php
$string['downloadcoursecontent'] = 'Télécharger les contenus du cours';
et dans racinedetonsite/moodledata\lang\fr\role.php
$string['course:downloadcoursecontent'] = 'Télécharger les contenus du cours';
Sur mon site moodle je vois bien ceci:
That question type does have a mobile sub-folder with 2 files, oumr.html and oumr.js but questions created with this question type do not work in the Mobile App, the question text is displayed but the choices do not appear.