It's the secret to her ability to spout out ice cream koans...
Err, without delving into Wikispeak, she's showing off the "The Complete Quotes and Quotations List, Spring 2013 Edition." Probably the source of all those weird saying she keeps using throughout the episodes.
The Super
Da-JirinLiterally, "Rubbish forest of words".
It's a parody of Sanseido(u)'s Japanese dictionary, "Daijirin ("Great forest of words"). See also its Wikipedia article.
2013 Spring EditionThe Complete Quotes and Quotations List