That location is the Program, not the Library

BUT

I see strangeness... LOTS
the x86 part says 32bit program...
BUT a Library is NOT a program, nor kept there.
BUT 'Calibre Book Hold' is not part of the program, nor standard Library name.
The
part-0001.calibre-data' IS a piece of an EXPORTED Library (part of an
Library image . there should have been other chunks there also).
If this HD has the actual library, locate that (search the disk for
metadata.db) THAT FOLDER
is a Library.
Usu it in place or MOVE THE FOLDER to a new home.
Switch/Create: Use Existing is how to direct Calibre to any existing Library (you can have many)

The FOLDER name is the Library name. You can change that as part of the move, you will just need to use the Switch/Create to point at its new name