diff --git a/Userland/Libraries/LibWeb/XHR/XMLHttpRequest.h b/Userland/Libraries/LibWeb/XHR/XMLHttpRequest.h
index 4b025f21b9..2470323855 100644
--- a/Userland/Libraries/LibWeb/XHR/XMLHttpRequest.h
+++ b/Userland/Libraries/LibWeb/XHR/XMLHttpRequest.h
@@ -23,6 +23,7 @@
 
 namespace Web::XHR {
 
+// https://fetch.spec.whatwg.org/#typedefdef-xmlhttprequestbodyinit
 using XMLHttpRequestBodyInit = Variant<NonnullRefPtr<FileAPI::Blob>, NonnullRefPtr<URL::URLSearchParams>, String>;
 
 class XMLHttpRequest final