Add Files from Calibre Library

I use Calibre to organize my digital book files and transfer to my reader.
When I use the Add Books and Scan the folder, I get the epub and any other formats listed and the OPF file as entries.
Where it found multi formats for the same book will show them as separate entries or group under one entry?
Why is it listing the OPF file, is that a valid book format to the program or is going to read it and fill in some of the fields?
Lastly there is usually a Cover.jpg file, can that be added for the cover automatically?

Book Collector can scan a folder, and you set up how it will parse the file/string


As you can see it bundled all 3 “formats” of the Potter book in 1 item. And it will link all those book files to that book when I add it.

Also, you can see top right, I’ve set it up to use the right format, namely “Author - Title.ext”

OPF is a format that is found and added by this screen. It does not read “inside”.

Detecting Cover.jpg is not done by Book Collector. I’ve taken note of your request to have that added.