$ git clone -n https://src.fedoraproject.org/rpms/rust-serde-untagged.git /var/lib/mock/f45-build-44839-818/root/chroot_tmpdir/scmroot/rust-serde-untagged
Cloning into '/var/lib/mock/f45-build-44839-818/root/chroot_tmpdir/scmroot/rust-serde-untagged'...
$ git fetch origin c44d8f73fd53e057254da4e1718f429aaee05246:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde-untagged
 * [new ref]         c44d8f73fd53e057254da4e1718f429aaee05246 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c44d8f7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild