Honzuki no Gekokujou ~Shisho ni Naru Tame ni wa Shudan wo Erandeiraremasen~ Dai 3-bu 「Ryouchi ni Hon o Hirogeyou!」 - Vol. 1 Ch. 4

[MangaDex]

 

[Quarnozian]

Meta joke, as this is a book where she is the protagonist, and "you're ok in my book" is literally in her book.

Not sure if the meta joke is also in the japanese version.

 

[Grimmycoffee]

Whohoo, she got her library!

 

[jslblaze]

Spoiler: Yay! P5V8

hey look, it’s the key to the foundation. She can now become Aub Ehrenfest whenever she wants.