$ git clone -n https://src.fedoraproject.org/rpms/R-crosstalk.git /var/lib/mock/f45-build-6065-346/root/chroot_tmpdir/scmroot/R-crosstalk
Cloning into '/var/lib/mock/f45-build-6065-346/root/chroot_tmpdir/scmroot/R-crosstalk'...
$ git fetch origin 5840fb3ec1655e8fbff10c946ad5ec48facadd4b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-crosstalk
 * [new ref]         5840fb3ec1655e8fbff10c946ad5ec48facadd4b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5840fb3 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild