$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rchardet.git /var/lib/mock/f45-build-35266-694/root/chroot_tmpdir/scmroot/rubygem-rchardet
Cloning into '/var/lib/mock/f45-build-35266-694/root/chroot_tmpdir/scmroot/rubygem-rchardet'...
$ git fetch origin 4bf0923e9a6da4b02837e7319e4e4b1b051ca913:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rchardet
 * [new ref]         4bf0923e9a6da4b02837e7319e4e4b1b051ca913 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4bf0923 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild