I just ran `make check` and got the following failing test:

FAIL: tests/guix-git-authenticate
=================================

+ '[' -d /home/rovanion/source/guix/main2/.git ']'
+ guile -c '(use-modules (git))
  (member "refs/heads/keyring" (branch-list (repository-open ".")))'
+ intro_commit=9edb3f66fd807b096b48283debdcddccfea34bad
+ intro_signer='BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA'
+ cache_key=test-30123
+ guix git authenticate 9edb3f66fd807b096b48283debdcddccfea34bad 'BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA' --cache-key=test-30123 --stats --end=9549f0283a78fe36f2d4ff2a04ef8ad6b0c02604
guix git: error: Git error: cannot locate remote-tracking branch 'keyring'
FAIL tests/guix-git-authenticate.sh (exit status: 1)

Running `make authenticate` and then rerunning `make check` did not resolve this issue.