response: Good question, I have no idea!  Another thing about a library is that it can be physical or virtual in nature, or indeed both.
original_response: since it is a virtual space, i believe the limit does not exist.
history: Hi! do you like E-books? Hmm well I can't read, I'm just a bot.  Did you know though that some e-books don't have a printed equivalent? No I didn't!   Do you know anything about Steve Howe? Oh, since 2015 he has been in a musical group with Alan White, Geoff Downes, Billy Sherwood and John Davison. Oh I see.  Hey what do you know about librarians? Librarians?  Oh I know that the role is constantly evolving, to meet technological and social needs. Oh I see.   I like libraries, what do you know about them? Um a library's a collection of information sources that are accessible for borrowing or reference. yup. I wonder how many books it can hold.
knowledge: It provides physical or digital access to material, and may be a physical building or room, or a virtual space, or both.