diff --git a/test/README.md b/test/README.md
index 94f77eda5148f2..5ed028a19631d6 100644
--- a/test/README.md
+++ b/test/README.md
@@ -379,3 +379,12 @@ The realpath of the 'tmp' directory.
 * return [<String>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type)
 
 Name of the temp directory used by tests.
+
+### WPT
+
+A port of parts of
+[W3C testharness.js](https://github.com/w3c/testharness.js) for testing the
+Node.js
+[WHATWG URL API](https://nodejs.org/api/url.html#url_the_whatwg_url_api)
+implementation with tests from
+[W3C Web Platform Tests](https://github.com/w3c/web-platform-tests).