As a tribute to the painless migration from the UI based load/save routines to
the API calls the function needed to return a string that could be used to
search the filepicker's filter list.
This however is deprecated so the function should be cleaned up to return the
filternames for the API so these can be used directly with the new
fileops-functions.

This is a task with a little risk to it as it might break tests anywhere, a full
fledged test cycle is required to ensure nothing breaks.