VS Code with PHP and Xdebug 3 Xdebug 3 is an extremely powerful debugging tool for PHP. Although print_r(), var_dump() and dd() have their uses, Xdebug gives more powerful debugging options: step debugging allows the ability to view execution of each line of code, including the ability to view all variables and their values. Code coverage is useful to identify untested code, or code which is never executed (dead code).