What are the top Lean repos?

Popular Lean repositories on GitHub, each answered in plain English for non-coders: what it is, its tech stack, and how to run it.

jzshischolar/pyleanerPyLeaner bridges Python and Lean 4 so AI researchers can query formal proof state, extract theorem definitions
mathtensor/ai4math-putnam2025Lean 4 formal proofs for all twelve 2025 Putnam Competition problems, machine-verified against Mathlib and pin
cajal-technologies/talosA WebAssembly interpreter built in Lean 4 that lets you mathematically prove what a program will do for all po