How to specify labels on configs/secrets

With the compose-file documentation it is not obvious how you specify labels, yet if you use docker config inspect command it suggests one can apply labels to a configuration.

Is there a way to specify a label on a config (or secret) using the compose file?

Looking at the schema of compose, it seems to me that the labels are not yet configurable with compose:
config_schema_v3.4.json

You could create the configs using the CLI and just point to the external config using external: true within your compose file.