diff --git a/lib/docs/main.js b/lib/docs/main.js
index 4afe1f96dd..0402f0f6af 100644
--- a/lib/docs/main.js
+++ b/lib/docs/main.js
@@ -2375,6 +2375,9 @@ const NAV_MODES = {
                   if (paramName != null) {
                     // skip if it matches the type name
                     if (!shouldSkipParamName(paramValue, paramName)) {
+                      if (paramName === "") {
+                        paramName = "_";
+                      }
                       payloadHtml += paramName + ": ";
                     }
                   }