[Theme Horse Support Team]

Hi contact,

If you need code customisation then We recommended not to change the code because if you change the code then while updating to our new version all your customisation code will be lost. So better make child theme and first unhook the functions and the edit the code.

http://codex.wordpress.org/Child_Themes

The file is inside interface (theme folder) -> inc -> structure -> content-extension.php

Thank you!