The path stems from the debug symbols the compiler emits. We compile our builds with GitHub actions, which places the source tree in D:\a\spine-runtimes.

The actual error is:

No loader found for resource: res://.godot/exported/133200997/export-8979be626377eb1fcf5ed7cd4f2f0072-cat_spine_skeleton_data_resource.res (expected type: SpineSkeletonDataResource)

Which means you are using an Android export template that does not have spine-godot support, which makes sense, as spine-godot + C# is currently limited to desktop operating systems and web. See:

EsotericSoftware/spine-runtimes2442

It is also indicated on the download page:

I'm currently working on turning spine-godot into a GDExtension, which should hopefully also enable C# support on Android and iOS.

We are happy to announce the general availability of spine-ios! Learn more about spine-ios on our blog.

Probably you need to use the same editor version to export your data that matches the version of the runtime in the app. Alternatively, you can use the matching version of Skeleton Viewer:
http://esotericsoftware.com/spine-skeleton-viewer

If you have a Spine license you can run the matching version of the Spine editor and import the data.