metafield:
Metafield
A [custom field](https://shopify.dev/docs/apps/build/custom-data),
including its `namespace` and `key`, that's associated with a Shopify resource
for the purposes of adding and storing additional information.
metafieldsByIdentifiers:
Metafield!
The metafields associated with the resource matching the supplied list of namespaces and keys.
privateMetafield:
PrivateMetafield
Returns a private metafield by namespace and key that belongs to the resource.