Nominally, questions work internally by grading the students response on a scale of 0 to 1, called fraction.

Except that, since the new question engine was created, we have allowed question grades to go down below zero, no 'minfraction'.

Now, to make the certainty-based marking behaviours work better, we are introducing maxfraction, which can be greater than 1.

To implement this, I simply searched the code for 'minfraction' and everywhere that was mentioned, implemented an equivalent 'maxfraction', defaulting to 1, to replace the hard-coded, or implicit, 1.