Launchers copy a player's prepared resources to a new release while its preparer declares the
same OUTPUT_VERSION (the launcher side is its own pull request). The number is bumped by hand;
CI keeps it honest: the parity job already prepares with every change to the preparer, and
tools/prepare_output.py check now fails when that preparation's digest is not the one
crates/horizon-prepare/output-versions.txt gives the current number, or when the file changed
other than by appending a version. The digest canonicalises what differs between two runs of
the same preparer (JSON key order, creative tab tag order, lambda class addresses, logs, the
sounds): 10 preparations by 5 preparer versions on the three Mac runners give one digest, and a Linux preparation by an older preparer gives the Mac runners' digest for it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>