copyright library
A library that receives a copy of every publication in a country by legal deposit, often for copyright registration and preservation. In computing contexts, may refer to digital copyright deposit systems.
The copyright library in the UK holds a copy of every book published in the country.
The construction of a digital copyright library is underway.
法定納本図書館 is a broader term for any legal deposit library, while 著作権図書館 specifically emphasizes the copyright registration aspect.
Compound of 著作権 (copyright) and 図書館 (library). A straightforward modern term with no obscure historical derivation.