It does not seem like setting a header in a response as required makes any difference

Hi Tom_S ,

Thank you for the prompt reply :-)

When you write:

However, for headers, even though they can be defined as required (required: true), Swagger UI does not display a red asterisk or similar indicator for them. This is by design and not an issue with the tool. The required header will still be enforced during validation.

I assume you mean required fields on headers in responses - because it works fine for headers in requests: