define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true ); // or define( 'WP_DEBUG_LOG', '/tmp/wp-errors.log' )
define( 'WP_DEBUG_DISPLAY', true );
Source: https://wordpress.org/documentation/article/debugging-in-wordpress/
Notes about WordPress Gutenberg themes development.
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true ); // or define( 'WP_DEBUG_LOG', '/tmp/wp-errors.log' )
define( 'WP_DEBUG_DISPLAY', true );
Source: https://wordpress.org/documentation/article/debugging-in-wordpress/