If the file
config.php does not exist in
site/config directory then create one and set debug to
<?php return [ 'debug' => true, ];
This will log out any error with a useful message in your browser when something is not right.
You probably don't want to log this error in production. Therefore you can create a second config file for working locally. So let's set the already created
config.php file debug property to
false. And create another config file for development only. Next to config.php create
config.localhost.php and set the debug propery to
true. This way debug mode will only be set to true when domain is localhost.