$ git clone -n https://src.fedoraproject.org/rpms/rust-json5.git /var/lib/mock/f45-build-42764-796/root/chroot_tmpdir/scmroot/rust-json5
Cloning into '/var/lib/mock/f45-build-42764-796/root/chroot_tmpdir/scmroot/rust-json5'...
$ git fetch origin 758a7e2a9a24aacc1dbbb96354012e804b89cd00:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-json5
 * [new ref]         758a7e2a9a24aacc1dbbb96354012e804b89cd00 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 758a7e2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild