What is a filter and how do I use it ?
A filter is a small piece of code you add to your functions.php theme file. It allows you (if the plugin is designed for using filters) to modify the behavior of the plugin, without modifying it.
Quick export plugin offers a lot of filters you can use this way to customize your export. Most of the filters are illustrated in the FAQ.
(Be careful, if you use a premium theme, if you update it it will probably erase the you you add in the functions.php file. But most of times there are specific file in your theme you can edit, which are update-proof.)