$ git clone -n https://src.fedoraproject.org/rpms/R-pkgbuild.git /var/lib/mock/f45-build-6302-347/root/chroot_tmpdir/scmroot/R-pkgbuild
Cloning into '/var/lib/mock/f45-build-6302-347/root/chroot_tmpdir/scmroot/R-pkgbuild'...
$ git fetch origin b965969287dc3362b6c4e0b5152001923ace3ee4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pkgbuild
 * [new ref]         b965969287dc3362b6c4e0b5152001923ace3ee4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b965969 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild