How do to access 'Category Metafields' in Liquid?

Technical Q&A
8

You can assign a product to a category and then a list of category metafields will become available on the product.

You can access them in the same way as standard metafields, but using the shopify namespace.

To see the namespace, key and return type (in this case metaobject (list)), check the relevant metafield definition here:
https://admin.shopify.com/store//settings/custom_data/product/metafields

Example:

{% liquid
  assign firstProduct = collections["all"].products.first
  assign sizeMetafield = firstProduct.metafields.shopify.size.value
%}
<script>
  console.log("productId", {{ firstProduct.id }});
  console.log("sizeMetafield", {{ sizeMetafield | json }});
</script>

There is some confusion in these comments around options, which is perhaps because you can link these category metafields to the product options, and they would therefore display the same name, but options and category metafield values are not necessarily linked.