(see also https://github.com/google/zoekt/issues/81) It looks like git 2.21 included a regression. The command git clone --bare --progress \ --config "remote.origin.fetch=+refs/heads/*:refs/heads/*" \ https://github.com/google/zoekt.git \ /tmp/zoekt-git2.20.git would succeed with git 2.20, but fails with fatal: multiple updates for ref 'refs/heads/master' not allowed in git 2.21, probably caused by commit 515be83. Should I call git in another way? I originally included "remote.origin.fetch=+refs/heads/*:refs/heads/*" to avoid getting Gerrit refs (refs/changes/*), but maybe I should use a different incantation? -- Google Germany GmbH, Erika-Mann-Strasse 33, 80636 Munich Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Geschäftsführer: Paul Manicle, Halimah DeLaine Prado