$ git clone -n https://src.fedoraproject.org/rpms/R-Cairo.git /var/lib/mock/f41-build-side-1-3143539-40012/root/chroot_tmpdir/scmroot/R-Cairo
Cloning into '/var/lib/mock/f41-build-side-1-3143539-40012/root/chroot_tmpdir/scmroot/R-Cairo'...
$ git fetch origin d2b72171b8d1a64828260b67e0491095f42bde3d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-Cairo
 * [new ref]         d2b72171b8d1a64828260b67e0491095f42bde3d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d2b7217 convert GPLv2 license to SPDX