Location? Do you mean something from the user profile?
Anyway, the code is in mod/quiz/report/overview/report.php
Roughly speaking it first builds some complex SQL to load the data from the database. Find where it gets things like the user firstname, and add town, country there.
Next it builds a table object in memory with rows and columns. There you need to add a heading for the new data, and then add the data to each row.