$ git clone -n https://src.fedoraproject.org/rpms/perl-B-Hooks-AtRuntime.git /var/lib/mock/f43-perl-60958861-6586769/root/chroot_tmpdir/scmroot/perl-B-Hooks-AtRuntime
Cloning into '/var/lib/mock/f43-perl-60958861-6586769/root/chroot_tmpdir/scmroot/perl-B-Hooks-AtRuntime'...
$ git fetch origin c771c814ee3e0cda852fd607c948c511a36ab904:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-B-Hooks-AtRuntime
 * [new ref]         c771c814ee3e0cda852fd607c948c511a36ab904 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c771c81 Perl 5.42 rebuild