You may want to throw exceptions from time to time. The framework has an exception handler installed. You can control its behaviour via the APP_DEBUG variable (located in your .env file). If this variable is set to true then every output of an exception will show on as output in your browser. You can edit the layout if you want in the file
app/views/error/exception_debug.php.
If it is set to false (or does not exist) then there will just be an error shown in your browser. This is useful to hide those debug messages from your clients. You can edit its layout in the file
app/views/error/exception_prod.php.
Exceptions are also appended to the log buffer.