How to filter and remove entries with missing files?

My database was generated by importing a folder with (unlinked) PDF files. Later I deleted some of the files (outside JabRef). Now I want to remove the corresponding records from the database. I don’t know a way of doing, besides scrolling through each record and checking if the “File” field is highlighted yellow/orange.

Is there a way of selecting and removing records with broken file links from the database?

If this functionality is missing, I propose extending the search query language with flags or fictitious fields, e.g., “file=pdf file_valid=false”.

Related discussion: