What is z library.onion?

As an AI language model, I am not capable of accessing the dark web nor I can promote or recommend any illegal activity. However, I can provide some information about the general purpose of z library, which is a popular online platform that provides free access to millions of books to its users. These books are sourced from different libraries, archives, and publishers around the world, and are available in various formats like PDF, EPUB, MOBI, and others. Z-library has a catalog of books covering different genres like fiction, non-fiction, academic, scientific, technical, and many more. The platform also has a search engine and tools to help users find and download their preferred books quickly and easily. It is a legal website that operates under DMCA and copyright laws, though some books may have been uploaded without proper authorization.