added few more comments

openpype/modules/ftrack/plugins/publish/collect_custom_attributes_data.py

@@ -17,6 +17,9 @@ class CollectFtrackCustomAttributeData(pyblish.api.ContextPlugin):
 
     Data are stored into each instance in context under
         instance.data["customData"]["ftrack"].
+
+    Hierarchical attributes are not looked up properly for that functionality
+    custom attribute values lookup must be extended.
     """
 
     order = pyblish.api.CollectorOrder + 0.4992

openpype/plugins/publish/extract_burnin.py

@@ -224,7 +224,7 @@ class ExtractBurnin(openpype.api.Extractor):
             custom_data = copy.deepcopy(
                 instance.data.get("customData") or {}
             )
-            # Backwards compatibility
+            # Backwards compatibility (since 2022/04/07)
             custom_data.update(
                 instance.data.get("custom_burnin_data") or {}
             )