WordPress at a glance
function is not described

_wp_render_title_tag() WP 4.1.0

Displays title tag with content.

  • Since 4.4.0 Improved title output replaced wp_title().

No Hooks.

Return

Nothing (null).

Usage

_wp_render_title_tag();

Code of wp render title tag: wp-includes/general-template.php WP 5.2.1

<?php
function _wp_render_title_tag() {
	if ( ! current_theme_supports( 'title-tag' ) ) {
		return;
	}

	echo '<title>' . wp_get_document_title() . '</title>' . "\n";
}