In his science fiction novel Diaspora, Greg Egan describes a virtual environment called the Truth Mines. His characters are mind constructs living in virtual reality, and the Truth Mines are one of the 'scapes' they can go to.

In one sense, the Truth Mines were just another indexscape. Hundreds of thousands of specialized selections of the library's contents were accessible in similar ways -- and Yatima had climbed the Evolutionary Tree, hopscotched the Periodic Table, walked the avenue-like Timelines for the histories of fleshers, gleisners, and citizens. Half a megatau before, ve'd swum through the Eukaryotic Cell; every protein, every nucleotide, every carbohydrate drifting through the cytoplasm had broadcast gestalt tags with references to everything the library had to say about the molecule in question.
In the Truth Mines though, the tags weren't just references; they included complete statements of the particular definitions, axioms, or theorems the objects represented. The Mines were self-contained: every mathematical result that fleshers and their descendants had ever proven was on display in its entirety. The library's exegesis was helpful - but the truths themselves were all there.

Yatima, the book's protagonist, is a citizen of Konishi polis, a community in which Truth Mining is held in high regard. New Miners explore the Mines, cutting deeper and deeper, learning more and more, until eventually they reach a dead end; new results could be proven based on this point, but no-one has done so yet. Because the number of proofs is infinite, and the corridors in the Mines branch exponentially, writing bot software to do this is impossible. So, over the centuries, Truth Miners keep expanding the huge knowledge base.

Not just that; being a pure mathematical construct verself (although originally based on models of actual humans), Yatima is on a quest to find verself. Ve reasons that if ve knows all ve will ever know, ve can compare verself with what ve has become. Ver Self will be that part that has remained the same over all the eons. Yatima can't work on this full-time, ve only has time in between all the adventures that make up the book.

So, to summarize: this novel has far future AIs, who live in a community of citizens who node for the ages, to build a self-contained knowledge base, as a pastime. It might remind you of something...

The irritating gender neutral pronouns I used in this write-up are there to be compatible with the quotes from the book.