$ git clone -n https://src.fedoraproject.org/rpms/R-assertthat.git /var/lib/mock/f41-build-side-1-2630570-25600/root/chroot_tmpdir/scmroot/R-assertthat
Cloning into '/var/lib/mock/f41-build-side-1-2630570-25600/root/chroot_tmpdir/scmroot/R-assertthat'...
$ git fetch origin 6eeae140f6e34c63ddf74fb48f84bf957a83ca6d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-assertthat
 * [new ref]         6eeae140f6e34c63ddf74fb48f84bf957a83ca6d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6eeae14 convert GPLv3 license to SPDX