diff -r 34716fd837a4 -r be944660c56a wp/wp-includes/rest-api/search/class-wp-rest-term-search-handler.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/rest-api/search/class-wp-rest-term-search-handler.php	Wed Sep 21 18:19:35 2022 +0200
@@ -0,0 +1,156 @@
+<?php
+/**
+ * REST API: WP_REST_Term_Search_Handler class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 5.6.0
+ */
+
+/**
+ * Core class representing a search handler for terms in the REST API.
+ *
+ * @since 5.6.0
+ *
+ * @see WP_REST_Search_Handler
+ */
+class WP_REST_Term_Search_Handler extends WP_REST_Search_Handler {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 5.6.0
+	 */
+	public function __construct() {
+		$this->type = 'term';
+
+		$this->subtypes = array_values(
+			get_taxonomies(
+				array(
+					'public'       => true,
+					'show_in_rest' => true,
+				),
+				'names'
+			)
+		);
+	}
+
+	/**
+	 * Searches the object type content for a given search request.
+	 *
+	 * @since 5.6.0
+	 *
+	 * @param WP_REST_Request $request Full REST request.
+	 * @return array Associative array containing an `WP_REST_Search_Handler::RESULT_IDS` containing
+	 *               an array of found IDs and `WP_REST_Search_Handler::RESULT_TOTAL` containing the
+	 *               total count for the matching search results.
+	 */
+	public function search_items( WP_REST_Request $request ) {
+		$taxonomies = $request[ WP_REST_Search_Controller::PROP_SUBTYPE ];
+		if ( in_array( WP_REST_Search_Controller::TYPE_ANY, $taxonomies, true ) ) {
+			$taxonomies = $this->subtypes;
+		}
+
+		$page     = (int) $request['page'];
+		$per_page = (int) $request['per_page'];
+
+		$query_args = array(
+			'taxonomy'   => $taxonomies,
+			'hide_empty' => false,
+			'offset'     => ( $page - 1 ) * $per_page,
+			'number'     => $per_page,
+		);
+
+		if ( ! empty( $request['search'] ) ) {
+			$query_args['search'] = $request['search'];
+		}
+
+		/**
+		 * Filters the query arguments for a REST API search request.
+		 *
+		 * Enables adding extra arguments or setting defaults for a term search request.
+		 *
+		 * @since 5.6.0
+		 *
+		 * @param array           $query_args Key value array of query var to query value.
+		 * @param WP_REST_Request $request    The request used.
+		 */
+		$query_args = apply_filters( 'rest_term_search_query', $query_args, $request );
+
+		$query       = new WP_Term_Query();
+		$found_terms = $query->query( $query_args );
+		$found_ids   = wp_list_pluck( $found_terms, 'term_id' );
+
+		unset( $query_args['offset'], $query_args['number'] );
+
+		$total = wp_count_terms( $query_args );
+
+		// wp_count_terms() can return a falsey value when the term has no children.
+		if ( ! $total ) {
+			$total = 0;
+		}
+
+		return array(
+			self::RESULT_IDS   => $found_ids,
+			self::RESULT_TOTAL => $total,
+		);
+	}
+
+	/**
+	 * Prepares the search result for a given ID.
+	 *
+	 * @since 5.6.0
+	 *
+	 * @param int   $id     Item ID.
+	 * @param array $fields Fields to include for the item.
+	 * @return array Associative array containing all fields for the item.
+	 */
+	public function prepare_item( $id, array $fields ) {
+		$term = get_term( $id );
+
+		$data = array();
+
+		if ( in_array( WP_REST_Search_Controller::PROP_ID, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_ID ] = (int) $id;
+		}
+		if ( in_array( WP_REST_Search_Controller::PROP_TITLE, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_TITLE ] = $term->name;
+		}
+		if ( in_array( WP_REST_Search_Controller::PROP_URL, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_URL ] = get_term_link( $id );
+		}
+		if ( in_array( WP_REST_Search_Controller::PROP_TYPE, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_TYPE ] = $term->taxonomy;
+		}
+
+		return $data;
+	}
+
+	/**
+	 * Prepares links for the search result of a given ID.
+	 *
+	 * @since 5.6.0
+	 *
+	 * @param int $id Item ID.
+	 * @return array Links for the given item.
+	 */
+	public function prepare_item_links( $id ) {
+		$term = get_term( $id );
+
+		$links = array();
+
+		$item_route = rest_get_route_for_term( $term );
+		if ( $item_route ) {
+			$links['self'] = array(
+				'href'       => rest_url( $item_route ),
+				'embeddable' => true,
+			);
+		}
+
+		$links['about'] = array(
+			'href' => rest_url( sprintf( 'wp/v2/taxonomies/%s', $term->taxonomy ) ),
+		);
+
+		return $links;
+	}
+}