WordPress at a glance
function is not described

display_header_text() WP 3.4.0

Whether to display the header text.

No Hooks.

Return

true/false.

Usage

display_header_text();

Code of display header text: wp-includes/theme.php VER 5.0.3

<?php
function display_header_text() {
	if ( ! current_theme_supports( 'custom-header', 'header-text' ) )
		return false;

	$text_color = get_theme_mod( 'header_textcolor', get_theme_support( 'custom-header', 'default-text-color' ) );
	return 'blank' !== $text_color;
}