Manual:Php.ini
php.ini это конфигурационный файл PHP.
This file will sometimes need to be modified; e.g. it might be necessary to set xdebug.max_nesting_level = 200 if you get the error "Fatal error: Maximum function nesting level of '100' reached, aborting!" After you make changes, use /usr/local/apache/bin/apachectl graceful to reload the config files without actually killing the webserver and starting it back up.
If you are looking to enable/disable upload settings see LocalSettings.php
Расположение файла
Некоторые PHP установки имеют 2 php.ini файла, один отвечает за php_sapi модуль, который обрабатывает запросы веб-сервера, а другой для командной строки PHP. The former is used to adjust, for example, file size limits for image uploads.
To find the configuration file for the web module, create a sample php file with this content:
<?php
phpinfo();
and access it from the web server. It should display a lot of information about your PHP installation, including the location of the php.ini file.
To find the configuration file for the command line binary, use php --ini.