My preferred bibliographic format is Modern Language Association 9th edition. I often use the "Extra" field to hold information about book illustrators. Right now the preview/export shows a comma after "Illustrated by ... ". I simply want to change this comma to a period. This is for personal use and I am not in any way suggesting a permanent change, since my primary use of Zotero is personal. I've tried looking at where in the source code to make this change but so far have been unsuccessful. Need guidance as to where to go to change just that one character. Thanks!