$ git clone -n https://src.fedoraproject.org/rpms/R-fastmap.git /var/lib/mock/f45-build-6043-346/root/chroot_tmpdir/scmroot/R-fastmap
Cloning into '/var/lib/mock/f45-build-6043-346/root/chroot_tmpdir/scmroot/R-fastmap'...
$ git fetch origin 3edb0d7f36f7ce082d0fd9891b17be5099c88f99:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-fastmap
 * [new ref]         3edb0d7f36f7ce082d0fd9891b17be5099c88f99 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3edb0d7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild