In Mac OS 10.15 Catalina you can see three folders in the path
- Local volume.
In previous versions of the operating system I could only find the "Volume" folder with index files for Spotlight.
The easy answer seems to be that "LocalVolume" is for local disks and "Volume" is for shared server volumes, for example, but when I tried to index the shared network volumes (on a client) I could find the new index files in the folder "LocalVolume".
I have searched but I have not been able to find any type of document that explains this. It's important to understand this to find solutions for index problems in a macOS Catalina client/server environment.