ProtonKK

A tiny Koikatsu-tuned flavor of CachyOS Proton. It's the exact same Proton build — just with the launch options that modded Koikatsu wants baked in, so you pick it from the dropdown and play. No %command% string, no per-game env vars, works the same in Steam, Heroic, Lutris, or anything else that reads Steam compatibility tools.

What it bakes in

Selecting ProtonKK as your compatibility tool is equivalent to launching with:

PROTON_FORCE_LARGE_ADDRESS_AWARE=1 PROTON_HEAP_DELAY_FREE=1 \
PROTON_NO_WRITE_WATCH=1 WINEDLLOVERRIDES="winhttp=n,b" DXVK_ASYNC=1 %command%

Variable	Why (for modded KK)
PROTON_FORCE_LARGE_ADDRESS_AWARE=1	4GB+ address space for 32-bit KK — essential once mods/HardMods stack up.
PROTON_HEAP_DELAY_FREE=1	Smooths allocation churn from heavy mod loads.
PROTON_NO_WRITE_WATCH=1	Wine-level hint. Not consumed by the current CachyOS proton script — kept for parity; harmless.
WINEDLLOVERRIDES=winhttp=n,b	Native winhttp for BepInEx/plugin updaters. Proton appends its own overrides on top; yours is preserved.
DXVK_ASYNC=1	Async shader compile — kills scene/card-load stutter.

FPS is left uncapped (no DXVK_FRAME_RATE) so Studio and high-refresh displays run free. Want the old 60 cap? Add "DXVK_FRAME_RATE": "60" to overlay/user_settings.py.

These are defaults, not a cage

Proton applies each value only if it isn't already set (if key not in self.env), so any per-game launch option or env var you set still wins over ProtonKK's default.

Install

From a release (recommended): download the latest ProtonKK-*.tar.xz and extract:

mkdir -p ~/.local/share/Steam/compatibilitytools.d
tar -xf ProtonKK-*-x86_64.tar.xz -C ~/.local/share/Steam/compatibilitytools.d

From source (builds against the latest upstream release — no compiling):

./install.sh          # builds if needed, then installs into compatibilitytools.d

Restart Steam → game Properties → Compatibility → ProtonKK (or set it globally under Steam Play). In Heroic, pick ProtonKK as the Wine/Proton version.

Build

./build.sh                      # latest upstream, x86_64
EDITION=x86_64_v3 ./build.sh    # modern-CPU optimized base
UPSTREAM_TAG=cachyos-11.0-20260702-slr ./build.sh   # pin a specific base

Artifacts land in dist/. The build just downloads the upstream CachyOS release tarball, overlays overlay/user_settings.py, rebrands the compat-tool manifest, and repacks — no Wine compilation involved.

Auto-updates

.github/workflows/build.yml checks CachyOS daily and cuts a matching protonkk-<upstream-tag> release automatically, so ProtonKK tracks upstream without manual work.

Credit

All the real engineering is CachyOS/proton-cachyos (and Valve's Proton beneath it). ProtonKK only overlays config. Licensed the same as upstream Proton (BSD-3-Clause); see the bundled LICENSE inside each build.