$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-JSON.git /var/lib/mock/f45-build-26702-618/root/chroot_tmpdir/scmroot/perl-Test-JSON
Cloning into '/var/lib/mock/f45-build-26702-618/root/chroot_tmpdir/scmroot/perl-Test-JSON'...
$ git fetch origin 51ab6455fa9581706337bd0de3838ebd450dc409:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-JSON
 * [new ref]         51ab6455fa9581706337bd0de3838ebd450dc409 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51ab645 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild