$ git clone -n https://src.fedoraproject.org/rpms/perl-JSON-Validator.git /var/lib/mock/f45-build-24319-603/root/chroot_tmpdir/scmroot/perl-JSON-Validator
Cloning into '/var/lib/mock/f45-build-24319-603/root/chroot_tmpdir/scmroot/perl-JSON-Validator'...
$ git fetch origin b294a8742f88b1a92b5456d1db8288e878d189c3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-JSON-Validator
 * [new ref]         b294a8742f88b1a92b5456d1db8288e878d189c3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b294a87 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild