$ git clone -n https://src.fedoraproject.org/rpms/rust-matugen.git /var/lib/mock/f45-build-43152-800/root/chroot_tmpdir/scmroot/rust-matugen
Cloning into '/var/lib/mock/f45-build-43152-800/root/chroot_tmpdir/scmroot/rust-matugen'...
$ git fetch origin 679bd91a5a555e6d2ff343ee4b7af2b02a5996e2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-matugen
 * [new ref]         679bd91a5a555e6d2ff343ee4b7af2b02a5996e2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 679bd91 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild