Usually it's a bad idea to mess with the core files. Do your tweaks inside the theme.
About the page to edit, usually is at the beginning of the index.php inside the theme folder, but can be in the header. Depends on how the theme is coded.

Either way it's pretty easy to find the loop, just look for ?wp_list_categories? on those files.
Solutho Reviewed by Solutho on . Invisible a selected category in main page Hi KWWH I need a suggestion, I have wordpress blog I want add porn category in my blog but I want my porn category never show in main/home page. If any one want to see porn then he need to click on Porn category. I know it possible in DLE and other CMS but dont know how to do this in wordpress? Please help me. Rating: 5