The Steamworks SDK is not committed and is not shipped in the npm package. Maintainer builds expect an unpacked SDK at:
.sdk/sdk
The folder should contain the normal Steamworks layout:
.sdk/sdk/public/steam
.sdk/sdk/redistributable_bin
To hydrate that folder in CI, upload a private steamworks-sdk.gz archive and
set:
STEAM_SDK_GZ_LINK
STEAM_SDK_GZ_SHA
STEAM_SDK_GZ_LINK may point to any URL that returns the archive bytes without
an interactive browser page. STEAM_SDK_GZ_SHA is required for downloaded
archives.
For local maintainer builds, place the archive at:
.sdk/steamworks-sdk.gz
npm run sdk:ensure unpacks that archive into .sdk/sdk.