Can I access ApiProxy 'spec' value containing the OpenApi or Swagger endpoint?

[#1]

I'm looking for a way to access the value stored in the ApiProxy tag called 'spec'. Below a part of it.

<APIProxy revision="1" name="TestApi">
    ........
    <Resources>
        <Resource>openapi://association.json</Resource>
    </Resources>
    <Spec>https://some-backendservice.com/docs/v1/swagger.json</Spec>
    ........
</APIProxy>

Is there a variable available for this?

I like to use this value to return the OpenApi or Swagger definition to the client and I don't want to define it more than once.