[Continuation] Continuation-key not available to end-users programatically?

I would like to use the “Continue A Pipeline” endpoint. However, it requires the continuation-key. I’ve tried all the docs and api routes, and it seems none return this key. I know it’s a dynamically generated env var, which shouldn’t be available to even print and copy manually when secrets masking is enabled. So, my question is how to get the continuation-key to use the continue pipeline’s endpoint?

Also, I’ve found this doc suggesting that the public continue endpoint should not be used by end-users. At this point, I assume that while it’s a public endpoint it should not be used outside of a circle config file: api-preview-docs/setup-workflows.md at master · CircleCI-Public/api-preview-docs · GitHub