$ git clone -n https://src.fedoraproject.org/rpms/rust-polling.git /var/lib/mock/f40-build-2251022-54102/root/chroot_tmpdir/scmroot/rust-polling
Cloning into '/var/lib/mock/f40-build-2251022-54102/root/chroot_tmpdir/scmroot/rust-polling'...
$ git fetch origin 939ce29ae1454b5870b7ecf8bc3d265cc4ebca10:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-polling
 * [new ref]         939ce29ae1454b5870b7ecf8bc3d265cc4ebca10 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 939ce29 Update to version 3.3.1; Fixes RHBZ#2251393