$ git clone -n https://src.fedoraproject.org/rpms/R-rhub.git /var/lib/mock/f45-build-6347-348/root/chroot_tmpdir/scmroot/R-rhub
Cloning into '/var/lib/mock/f45-build-6347-348/root/chroot_tmpdir/scmroot/R-rhub'...
$ git fetch origin 3ed574199872ec847be14580cbc19aace35966a5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rhub
 * [new ref]         3ed574199872ec847be14580cbc19aace35966a5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3ed5741 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild