$ git clone -n https://src.fedoraproject.org/rpms/rust-tempfile.git /var/lib/mock/f40-build-2234216-53391/root/chroot_tmpdir/scmroot/rust-tempfile
Cloning into '/var/lib/mock/f40-build-2234216-53391/root/chroot_tmpdir/scmroot/rust-tempfile'...
$ git fetch origin 8377de800cd4d11ef62bbef9b0655f514f451a1e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tempfile
 * [new ref]         8377de800cd4d11ef62bbef9b0655f514f451a1e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8377de8 Update to version 3.9.0; Fixes RHBZ#2256049