includes/Database/YDB.php
public function dead_or_error(\Exception $exception) {
        // Use any /user/db_error.php file
        if( file_exists( YOURLS_USERDIR . '/db_error.php' ) ) {
            include_once( YOURLS_USERDIR . '/db_error.php' );
            die();
        }

        $message  = yourls__( 'Incorrect DB config, or could not connect to DB' );
        $message .= '<br/>' . get_class($exception) .': ' . $exception->getMessage();

        yourls_die( yourls__( $message ), yourls__( 'Fatal error' ), 503 );
        die();
    }
public function dead_or_error(\Exception $exception) {
        // Use any /user/db_error.php file
        if( file_exists( YOURLS_USERDIR . '/db_error.php' ) ) {
            include_once( YOURLS_USERDIR . '/db_error.php' );
            die();
        }

        $message  = yourls__( 'Incorrect DB config, or could not connect to DB' );
        $message .= '<br/>' . get_class($exception) .': ' . $exception->getMessage();

        yourls_die( yourls__( $message ), yourls__( 'Fatal error' ), 503 );
        die();
    }
Die with an error message

@since  1.7.3

@param \Exception $exception

@return void