Which file is my reflection probe using?

Unity 2018.4
I have a reflection probe component on an object in my scene that’s used by several mesh objects.

How can I tell which cubemap (either auto-baked or manually baked) is in use by the probe?

And how do I set the cubemap for my probe - do I have to use a probe type of custom for that?

In particular I’m trying to export a scene from a project for use in another project, and it seems like the only thing not coming through in my asset export is the reflection probe’s cubemap.

Thanks for any advice!

After getting no bites here I also posted to the Global Illumination Forum and got a reply from unity:

https://forum.unity.com/threads/which-cubemap-file-is-my-auto-baked-reflection-probe-using.955689/#post-6228459

In short, there’s no way to tell which cubemap is being used from GI Cache when auto-baking. That’s really too bad.