I’m looking to appreciate “retro” Haskell projects, things from before stabilization/company use. Such as: ... BlueSpec compiler https://github.com/B-Lang-org/bsc

Note, the Bluespec compiler, though written in "retro" Haskell, remains in daily production use (as it has been, for 2 decades). Another project, written a few years ago but in totally "retro" style is Forvis, a complete executable spec for the RISC-V instruction set: https://github.com/rsnikhil/Forvis_RISCV-ISA-Spec Covers RV32 and RV64; unprivileged and privileged: unprivileged ISA: I (basic integer) M (integer multiply/divide) A (atomics) F, D (single and double precision floating point) C (compressed) privileged ISA: M (machine), S (supervisor) and U (user modes) Sv32, Sv39 and Sv48 virtual memory and has successfully booted a Linux kernel. Rgds, Nikhil