is attack on titan (shingeki no kyojin) episode 40 filler?

Historia Reiss remembers how she told Squad Levi about her upbringing. As a young girl, she grew up on a farm doing chores and other tasks, while her mother ignored her, spending her days reading.

As Historia learned to read herself, she began to realize that her situation was not normal, as parents were supposed to care for their children. One day, Historia tried to hug her mother like she had read about; however, her mother vehemently shoved her away, and lamented the fact that she was not able to kill Historia.

Even so, Historia was happy to have gotten any attention at all.