$ git clone -n https://src.fedoraproject.org/rpms/git.git /var/lib/mock/f40-build-763369-122473/root/chroot_tmpdir/scmroot/git
Cloning into '/var/lib/mock/f40-build-763369-122473/root/chroot_tmpdir/scmroot/git'...
$ git fetch origin f2b3ab26cc456c3905b9b19725937f0faa281d6c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/git
 * [new ref]         f2b3ab26cc456c3905b9b19725937f0faa281d6c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f2b3ab2 update to 2.43.0