LeanFrontier: nobody chose the version (Field Note 08)

LeanFrontier’s Field Note 08 records the corpus moving to Mathlib v4.33.1 on schedule, with the version chosen by nobody: the upgrade pipeline rebuilt the fingerprint index, re-audited all 114 entrypoints, replayed the kernel, and opened the pull request itself — a person only merged it. Getting there took three stacked defects, each invisible until the one before it was fixed, the best being a validator that refused the upgrade over bytecode it had compiled into its own working tree while running. A fourth outside contributor also sent in a submission, still open pending a rebase onto the new toolchain, and no acceptance was weakened by the upgrade.