diff --git a/doc/doap.xml b/doc/doap.xml
index 73c2c5da7..b43c4154a 100644
--- a/doc/doap.xml
+++ b/doc/doap.xml
@@ -724,6 +724,15 @@
         <xmpp:note>refers to inclusion of delay stamp in presence</xmpp:note>
       </xmpp:SupportedXep>
     </implements>
+    <implements>
+      <xmpp:SupportedXep>
+        <xmpp:xep rdf:resource="https://xmpp.org/extensions/xep-0334.html"/>
+        <xmpp:version>1.0.0</xmpp:version>
+        <xmpp:since>0.10.0</xmpp:since>
+        <xmpp:status>complete</xmpp:status>
+        <xmpp:note>Used in mod_carbons, mod_mam, and mod_muc</xmpp:note>
+      </xmpp:SupportedXep>
+    </implements>
     <implements>
       <xmpp:SupportedXep>
         <xmpp:xep rdf:resource="https://xmpp.org/extensions/xep-0352.html"/>
diff --git a/plugins/mod_mam/mod_mam.lua b/plugins/mod_mam/mod_mam.lua
index b57fc030b..ddceb0135 100644
--- a/plugins/mod_mam/mod_mam.lua
+++ b/plugins/mod_mam/mod_mam.lua
@@ -341,7 +341,6 @@ local function should_store(stanza) --> boolean, reason: string
 	end
 	if stanza:get_child("no-store", "urn:xmpp:hints")
 	or stanza:get_child("no-permanent-store", "urn:xmpp:hints") then
-		-- XXX Experimental XEP
 		return false, "hint";
 	end
 	if stanza:get_child("store", "urn:xmpp:hints") then
diff --git a/plugins/muc/history.lib.lua b/plugins/muc/history.lib.lua
index 005bd1d80..8d8fcf142 100644
--- a/plugins/muc/history.lib.lua
+++ b/plugins/muc/history.lib.lua
@@ -204,7 +204,6 @@ module:hook("muc-message-is-historic", function (event)
 	local stanza = event.stanza;
 	if stanza:get_child("no-store", "urn:xmpp:hints")
 	or stanza:get_child("no-permanent-store", "urn:xmpp:hints") then
-		-- XXX Experimental XEP
 		return false, "hint";
 	end
 	if stanza:get_child("store", "urn:xmpp:hints") then