Who is Anna Lefroy (nee Austen) from Jane Austen's Letters and what is their importance?

Anna Lefroy was born April 15, 1793. She married Benjamin Lefroy on November 8, 1814. The couple had one son and six daughters. Anna preserved some of her aunt's letters, and she provided James-Edward Austen with information to use in "Memoirs of Jane Austen". She died September 1, 1872.