Homebrew uses the main branch.
Run brew update to migrate.
Homebrew 1.0.0 (released 21 September 2016) is the oldest version that can bootstrap through this branch.
Without a master branch, Homebrew 4.5.9 (released 7 July 2025) is the oldest
version that can migrate to main. Installations with a stale origin/HEAD
may need to run brew update twice.
This migration will be removed on 1 March 2027.