See all previously imported entries

Sometimes I import several files in a row but then I loose track where they are and it is hard to find them again. Especially, if metadata is missing.

I have enabled the timestamp feature, thus it is at least possible to find the entries again by sorting the entry table. However I would like to have something like a computed group, which contains all entries that are added since the last start of jabref.

Maybe that would be possible if the timestamp field could be compared like timestamp >= 2021-02-01 or if special fields like today or sincestart are added.