Source

File: wp-includes/general-template.php

function single_term_title( $prefix = '', $display = true ) {
	$term = get_queried_object();

	if ( ! $term ) {
		return;
	}

	if ( is_category() ) {
		/**
		 * Filters the category archive page title.
		 *
		 * @since 2.0.10
		 *
		 * @param string $term_name Category name for archive being displayed.
		 */
		$term_name = apply_filters( 'single_cat_title', $term->name );
	} elseif ( is_tag() ) {
		/**
		 * Filters the tag archive page title.
		 *
		 * @since 2.3.0
		 *
		 * @param string $term_name Tag name for archive being displayed.
		 */
		$term_name = apply_filters( 'single_tag_title', $term->name );
	} elseif ( is_tax() ) {
		/**
		 * Filters the custom taxonomy archive page title.
		 *
		 * @since 3.1.0
		 *
		 * @param string $term_name Term name for archive being displayed.
		 */
		$term_name = apply_filters( 'single_term_title', $term->name );
	} else {
		return;
	}

	if ( empty( $term_name ) ) {
		return;
	}

	if ( $display ) {
		echo $prefix . $term_name;
	} else {
		return $prefix . $term_name;
	}
}