$ git clone -n https://src.fedoraproject.org/rpms/gprbuild.git /var/lib/mock/f45-build-12958-444/root/chroot_tmpdir/scmroot/gprbuild
Cloning into '/var/lib/mock/f45-build-12958-444/root/chroot_tmpdir/scmroot/gprbuild'...
$ git fetch origin e26f2266b3ae08444a962226ac80247d5a119e87:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gprbuild
 * [new ref]         e26f2266b3ae08444a962226ac80247d5a119e87 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e26f226 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild