Not-Augustine is what we call the woman Alex thinks is Augustine, but turns out not to be. Clear as mud, right? Not-Augustine is the last surviving person from Trachimbrod; in fact, she practically is Trachimbrod. She has tons of boxes filled with the memories of the destroyed shtetl. But we're not talking photographs and dishes; this is one of those symbolical lists:
Augustine has always been a collector, a "funny girl, always having little things in [her] heart" (18.11). Now she's equally funny (and by "funny" we mean cuckoo), with little things in boxes, like the world's nicest hoarder. She's so wrapped up in the past and her boxes that Alex even wonders if "it is possible that she is the last person on earth […] who does not know about America" (26.8).
So what happened to her, and why is she The Unofficial Keeper of the Shtetl™?
According to the story she tells Alex and his grandfather, it's pretty grim. During the attack on Trachimbrod, her sister was shot in the womb but lived. Her baby took the bullet and died. She herself crawled away, only to later return to Trachimbrod and recover everything she could. She then moves into a small house close to Trachimbrod (i.e. the house Not-Augustine now lives in).
Here's the thing: we think Not-Augustine might actually be her sister, and not in a "we are our own grandfather" time-travel sort of way. Notice that Not-Augustine never once mentions herself in this horrific story? It wouldn't be too strange for her to distance herself from the memory by imagining that it happened to someone else, to lessen the survivor's guilt. (Because she didn't die like everyone else, not because she auditioned for, and failed to get on, Survivor.)
After all, Not-Augustine is the one with all the memories of Trachimbrod stored in many boxes. Did she just inherit the house from her sister or did that sister never exist?
Before Alex, Jonathan, and his grandfather leave, we learn that this woman's real name is Lista P and that she thinks she still has a baby. Could this be the same baby who died during the Nazi raid? And whose baby does she think she has?
In the flashback chapters, we learn that Safran slept with a virgin widow named Lista. We're going to go out on a limb here and say that the dead baby just might have been a descendant of Safran. After all, he was the first man she had sex with and they saw each other shortly before the wedding, more than enough time for her to be pregnant and showing.
Finally, in the flashbacks, we see Safran give her the purple Hamlet book and he says, "You'll give it back to me one day" (27.162). When Lista describes the last time she saw Safran, all she says is they "had a fight about Ophelia. He made me cry, and I made him cry" (23.15).
Were they crying about the loss of the village—or the loss of their child? Or both?