$ git clone -n https://src.fedoraproject.org/rpms/R-processx.git /var/lib/mock/f45-build-6329-347/root/chroot_tmpdir/scmroot/R-processx
Cloning into '/var/lib/mock/f45-build-6329-347/root/chroot_tmpdir/scmroot/R-processx'...
$ git fetch origin 3a75542dde701777e5fcb56a06b81a069d74fa7e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-processx
 * [new ref]         3a75542dde701777e5fcb56a06b81a069d74fa7e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a75542 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild