AMP: Accelerated Mobile Pages / Product or Category Template Compile Errors
If you update your product or category AMP template and see:
Compiler error: readytheme is not in the list of valid items
it means your store is not a readytheme store and you will need to remove all references to readythemes from the product and category templates.
It's easy to do. When you are editing the template, remove each line that starts with:
<mvt:item name="readytheme"
Update the page and the compile error should disappear.