From rhn-support-tkonishi

There are two issues.

This section is in 2.5 - 2.9 docs, but the endpoint was implemented in 2.10; 2.5 to 2.9 don't have it. So please remove it from 2.5 to 2.9.
On the other hand, the section isn't in 2.10 and 2.11, so please add to 2.10 and 2.11.

Use the Proxy Configs List provider endpoint: <schema>://<admin-portal-domain>/admin/api/account/proxy_configs/<env>.json

The endpoint returns all stored proxy configs of the provider, not only the latest of each service. Iterate over the array of proxy_configs returned in the JSON and select the proxy_config.content whose proxy_config.version is the highest amongst all proxy configs with the same proxy_config.content.id, that is the ID of the service.

In 2.10 and 2.11 doc, this section is still there. Since this endpoint exists only on the SaaS version, please remove it from the on-premises docs.

Option 1. Download the configuration from the Admin Portal using the URL:

<schema>://<admin-portal-domain>/admin/api/nginx/spec.json

Consider the following:

The endpoint has limitations once 20 services have been exceeded.
You can see an example in: https://account-admin.3scale.net/admin/api/nginx/spec.json