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function is not described

_wp_render_title_tag() WP 4.1.0

Displays title tag with content.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

No Hooks.

Return

null. Nothing.

Usage

_wp_render_title_tag();

Changelog

Since 4.1.0 Introduced.
Since 4.4.0 Improved title output replaced wp_title().

Code of _wp_render_title_tag() WP 5.7.2

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

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