$ git clone -n https://src.fedoraproject.org/rpms/R-nycflights13.git /var/lib/mock/f45-build-6286-347/root/chroot_tmpdir/scmroot/R-nycflights13
Cloning into '/var/lib/mock/f45-build-6286-347/root/chroot_tmpdir/scmroot/R-nycflights13'...
$ git fetch origin 4a39459066a2900f567db7e440418364a8c36e46:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-nycflights13
 * [new ref]         4a39459066a2900f567db7e440418364a8c36e46 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4a39459 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild