The Library of Babel: The Repository of All Knowledge, which arguably is the Empire’s equivalent of the Library of Congress, except that it’s been around for long enough – millennia – that it’s also the unburnt Library of Alexandria; and is available to the general public, under the conditions of its charter. And much like those, it is very, very good at indexing every piece of information it can get its hands on, including archiving the entirety of their Internet-equivalent, and as much foreign media as it can get its hands on.
In short, its charter essentially reads: STORE ALL THE THINGS! It does its very best to live up to that, even the part of it that “wastes” tremendous amounts of data space on obsolete records and trivia. But then, the archivists know what happened to the last people to dismiss “trivia” too blithely, and that’s not going to happen again, not on their watch.
Of course, given the limitations of physical size, the complex, vast though it is, of cavernous bookshelf-lined rooms, dusty stacks, piles of stashed artifacts, and catacomb-like archives – not to mention the more obscure forms of recording knowledge – sitting in Calmirie, or even it in combination with all its branches and archival complexes scattered everywhere, are not the main part of the Repository, in terms of sheer density of information.
That would be, Isythila/Repository Prime, the 17th moon of Meliére (an outer gas giant in the capital system), roughly four miles in diameter, and – because you need quite a lot of space to STORE ALL THE THINGS – essentially hollow and stuffed to the brim with quantum-state storage devices, along with enough bandwidth to handle, shall we say, a quite unimaginable number of simultaneous requests. (There’re also its backup units, which have much the same physical conformation and capacity… but where those are located is one of the few pieces of information not to be stored somewhere in Repository Prime.)