What's the meaning of the U (update) in Reconciliation?

[ari gold]

Hi there,

I downloaded my credit card statement as a QFX file and have done File >
Import > Import OFX/QFX...

I think I understand (from reading the Packt Publishing book) how Gnucash
tries to match the file's entries to Gnucash's transactions.  What's not in
the book is the U+R or the "Update and reconcile (auto) match" option.

That is, why are some entries marked as R and some as U+R?

Thanks,

Ari