tl;dr: πfs is a satirical FUSE filesystem that "stores" your data in the digits of π, exploiting the conjecture that π is a normal number containing every possible finite sequence. In practice, it looks up each byte's location within π and saves those indices as metadata—meaning the "metadata" ends up larger than the original data, and writing a 400-line text file takes five minutes. The repo now points to a successor project, inferencefs.