$ git clone -n https://src.fedoraproject.org/rpms/rust-grep-printer.git /var/lib/mock/f40-build-2270962-54870/root/chroot_tmpdir/scmroot/rust-grep-printer
Cloning into '/var/lib/mock/f40-build-2270962-54870/root/chroot_tmpdir/scmroot/rust-grep-printer'...
$ git fetch origin 7026aa6fbdf9c4d73f9486d0e0979940edcbdd41:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-grep-printer
 * [new ref]         7026aa6fbdf9c4d73f9486d0e0979940edcbdd41 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7026aa6 Update to version 0.2.1; Fixes RHBZ#2251607