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.