$ git clone -n https://src.fedoraproject.org/rpms/mac.git /var/lib/mock/f40-build-733714-105363/root/chroot_tmpdir/scmroot/mac
Cloning into '/var/lib/mock/f40-build-733714-105363/root/chroot_tmpdir/scmroot/mac'...
$ git fetch origin 4739f9d2c25df8d0aa86ce493605d76cc7937203:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mac
 * [new ref]         4739f9d2c25df8d0aa86ce493605d76cc7937203 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4739f9d Convert to rpmautospec