diff --git a/packages/test-in-browser/driver.html b/packages/test-in-browser/driver.html
index 31c20deff3..249934ff8b 100644
--- a/packages/test-in-browser/driver.html
+++ b/packages/test-in-browser/driver.html
@@ -74,6 +74,20 @@
       {{/if}}
       {{#with get_details}}
         {{#if this}}
+          <!--
+            `type` can be any of the following or a
+            custom assertion type
+
+            * assert_equal
+            * instanceOf
+            * throws
+            * true
+            * null
+            * undefined
+            * NaN
+            * include
+            * length
+          -->
           {{#if type}}&mdash; {{type}}{{/if}}
           {{#each details}}
             - <span class="failkey">{{key}}</span> {{val}}