$ git clone -n https://src.fedoraproject.org/rpms/R-DynDoc.git /var/lib/mock/f45-build-5908-345/root/chroot_tmpdir/scmroot/R-DynDoc
Cloning into '/var/lib/mock/f45-build-5908-345/root/chroot_tmpdir/scmroot/R-DynDoc'...
$ git fetch origin e8e507c7a74f59d3fb7f292078f9a0220ed3b5e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-DynDoc
 * [new ref]         e8e507c7a74f59d3fb7f292078f9a0220ed3b5e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e8e507c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild