How to make collection_list accept a metafield?

Store Design
,
1

Trying to create a custom section for listing selected collections using

{
      "type": "collection_list",
      "id": "collectionthemelist",
      "label": "Collection Theme List"
    },

However, I can’t find the attribute to make this able to accept a metafield. However, the documentation states that “collection_list” accepts the metafield “list.collection_reference”. How?