is_tag() WordPress Function

function is_tag( $tag = '' ) {
	global $wp_query;

	if ( ! isset( $wp_query ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
		return false;
	}

	return $wp_query->is_tag( $tag );
}
Uses	Description
wp-includes/l10n.php:__()	Retrieve the translation of $text.
wp-includes/class-wp-query.php:WP_Query::is_tag()	Is the query for an existing tag archive page?
wp-includes/functions.php:_doing_it_wrong()	Mark something as being incorrectly called.
Used By	Description
wp-includes/rest-api.php:rest_get_queried_resource_route()	Gets the REST route for the currently queried object.
wp-includes/general-template.php:wp_get_document_title()	Returns document title for the current page.
wp-includes/general-template.php:get_the_archive_title()	Retrieve the archive title based on the queried object.
wp-includes/category-template.php:term_description()	Retrieves term description.
wp-includes/category-template.php:wp_list_categories()	Displays or retrieves the HTML list of categories.
wp-includes/general-template.php:feed_links_extra()	Display the links to the extra feeds such as category feeds.
wp-includes/general-template.php:wp_title()	Display or retrieve page title for all areas of blog.
wp-includes/general-template.php:single_term_title()	Display or retrieve page title for taxonomy term archive.
wp-includes/class-wp.php:WP::handle_404()	Set the Headers for 404, if nothing is found for requested URL.
wp-includes/post-template.php:get_body_class()	Retrieves an array of the class names for the body element.
wp-includes/canonical.php:redirect_canonical()	Redirects incoming links to the proper URL based on the site url.