I dragged the file from the file location into the Advanced field in Default Results.
It reports that it is a SnapGene DNA File.
Not sure how Alfred search scope is defined. On my iMac Alfred has been able to find these files since version 3 without using the "open" operator.
With an identical setup, on my MacBook Pro, Alfred requires the Open operator to see the files. It clearly can see the files, it just requires the open operator and I don't understand why. Spotlight sees the files too.
I have had this working on 3 other machines recent times so I'm not sure what other setting could be affecting this. Maybe there is another toggle setting I'm missing that is different between the machines.