I wonder if perhaps they are referring to The Author.
Yes, that would be the first part. STWA - The Author, followed by STWA - Unbroken. No idea what the next one will be, but there's supposed to be at least one more. Unbroken is also getting another book or two, right?
On another note, coming back to earlier discussions about Els' pacifism, and how it's not really pacifism. It's pretty clear on my new playthrough that it's her cover for her PTSD. Watching any violence, like the fights, brings on her PTSD attack, for example: after Val's first fight. She's comfortable with her inner violent tendencies, and tactical outlook, but doesn't want it out in the open. Since she was in Military Intelligence, she probably can't discuss anything in her military career, not specifically, so has to deal with the PTSD mostly herself. It's pretty tough.