$ git clone -n https://src.fedoraproject.org/rpms/rust-glycin.git /var/lib/mock/f42-build-side-1-3504987-45986/root/chroot_tmpdir/scmroot/rust-glycin
Cloning into '/var/lib/mock/f42-build-side-1-3504987-45986/root/chroot_tmpdir/scmroot/rust-glycin'...
$ git fetch origin 747d6dce48845f2e3f19373461f819803a125987:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-glycin
 * [new ref]         747d6dce48845f2e3f19373461f819803a125987 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 747d6dc Update to version 2.1.0; Fixes RHBZ#2352571