“I’m Here to Present You With an Opportunity… Barriss.”

We see that Lyn/Fourth Sister is interrogating a very familiar face: former Jedi Padawan, and prisoner of the Republic (now Empire), Barriss Offee. When we last saw Barriss, she was put on trial and jailed during the climactic events of Clone Wars season five, after staging a bombing at the Jedi Temple to protest the Order’s role in, and continued perpetration of, the Clone War—and attempting to pin the blame on her friend, Ahsoka Tano. Although Barriss was revealed as the true culprit and jailed, we now see she survived Order 66’s Jedi Purge—leaving her able to be swooped up by the Inquisitorius after the Republic’s fall.
Fun, grim note: Barriss is wearing a very similar prison uniform here. It matches one worn by her former master, Luminara Unduli, right down to a similar Mirialan headcover—or at least as a holoprojection of her was seen wearing in Star Wars Rebels’ first season, when Luminara’s corpse was used as a lure for Force sensitives to the Imperial prison facilities on the planet Stygeon Prime.