What do I do with them?
What do I do with them?
It depends on what you want to do. You mentioned both disabling the menu and editing the menu. If you want to disable the menu to test and see what happens, change the file extensions to .bak from .css and .php.
If you want to change the menu you'd edit the headermenu.php and tpl_drop_menu.php files.
The only file of those that exists is tpl_drop_menu.php and changing that to .bak made the entire home page go blank except for the header logo