$ git clone -n https://src.fedoraproject.org/rpms/rust-json.git /var/lib/mock/f45-build-42753-796/root/chroot_tmpdir/scmroot/rust-json
Cloning into '/var/lib/mock/f45-build-42753-796/root/chroot_tmpdir/scmroot/rust-json'...
$ git fetch origin 533983eba75699c64b2ee674904be8b08fcf69c1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-json
 * [new ref]         533983eba75699c64b2ee674904be8b08fcf69c1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 533983e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild