For proper syntax for HTL - please consult the HTL Spec here -- htl-spec/SPECIFICATION.md at master · adobe/htl-spec · GitHub

We are running this months ATCE on this subject with bslokiI strongly recommend that you sign up -- Scott's Digital Community: [Webinar | February ] Ask the AEM Community Expert: Best practice to query JCR data using Que…

Follow this article to learn how to create Editable Templates and pages based on them.Adobe Experience Manager Help | Creating an Adobe Experience Manager 6.4 website using Editable TemplatesYou can watch these short videos too:Scott's Digital Community: Guided Journey for Using Adobe Experience Man...

Team replied -- 1. add a simple custom include resource type based on /libs/granite/ui/components/coral/foundation/include/include.jsp, say /apps/my-project/include/include.jsp2. pass the parameters<myTas    jcr:primaryType="nt:unstructured"    sling:resourceType="/apps/my-project/include"    path="...

YOu have referenced the AEM docs for this topic. What is missing from that doc topic?

YOu are using the CODE in this article for a 6.3 AEM instance - is that correct?

Team replied:The script needs to have a logic to fin nodes that they are considering as orphan.Like it’s orphan because of a location, or name or type of node…There are a lot of sample on the net. For example: https://hashimkhan.in/aem-adobecq5-code-templates/groovy-script/

I checked with customer support - they have replied: They need to create a groovy script with some logic that they can use to run and delete it

See this AEM Docs topic - it will help you -- Revision Cleanup

As the reply suggests - you found a bug. Please open a support ticket so it gets fixed.