At minimum to run Lion formal verification using riscv-formal:
You'll need Yosys, SymbiYosys, and Boolector for the formal proofs. See here for intall instructions.
The nightly pipeline also has up-to-date steps to install Yosys, SymbiYosys, and Boolector.
If you want to inspect counter example traces or disassemble the code in the counter example traces see the ricsv-formal prerequisites.
Build: cabal build
Run checks: cabal run
Clean: cabal run formal -- clean