Thanks. I see something here, but they don't tell about the reasons to choose the orbit - which doesn't come too close to the Moon and has a period of a week (s

Thanks. I see something here, but they don't tell about the reasons to choose the orbit - which doesn't come too close to the Moon and has a period of a week (so in case of an emergency on a Moon base..?). And why it's called near-rectilinear. What's "South Earth-Moon L2 point"? There's just one Earth-Moon L2 point, right?