$ git clone -n https://src.fedoraproject.org/rpms/perl-Class-Can.git /var/lib/mock/f45-build-22311-590/root/chroot_tmpdir/scmroot/perl-Class-Can
Cloning into '/var/lib/mock/f45-build-22311-590/root/chroot_tmpdir/scmroot/perl-Class-Can'...
$ git fetch origin 81efff2314557f0a10147bf5a084a7a9553ab65b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Class-Can
 * [new ref]         81efff2314557f0a10147bf5a084a7a9553ab65b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 81efff2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild