Note: This is part of the developer docs and is considered custom code.
Unfortunately, we cannot provide support for custom code at this time as we do not have the additional resources that would be necessary to provide support for custom code.
If you need assistance with this, please reach out to our list of consultants for further assistance:
https://codeable.io/developers/restrict-content-pro/
Returns an array of post IDs that have post-level restrictions defined via the "Restrict this content" meta box.
The return value is saved in a transient for one day to help with performance.