The copy action allows you to copy the value of a field from one field to another. It takes two arguments: from, which specifies the source field, and to, which specifies the target field.

Here’s an example of how you might use the copy action in a YAML file:

actions:
  merge_filter:
    action: copy
    from: filters
    to: attribute_filters_filter

In this example, the copy action will copy the value of the filters field to the attribute_filters_filter field. If the filters field is empty or does not exist, the attribute_filters_filter field will also be empty or will not be created.