$ git clone -n https://src.fedoraproject.org/rpms/rust-gtk /var/lib/mock/f42-build-3429021-45391/root/chroot_tmpdir/scmroot/rust-gtk
Cloning into '/var/lib/mock/f42-build-3429021-45391/root/chroot_tmpdir/scmroot/rust-gtk'...
$ git fetch origin 34c482cbcf38aba03e85c877730007720b5a7b5f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gtk
 * [new ref]         34c482cbcf38aba03e85c877730007720b5a7b5f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 34c482c Update to version 0.18.2; Fixes RHBZ#2331131