$ git clone -n https://src.fedoraproject.org/rpms/R-flexiblas.git /var/lib/mock/f45-build-6205-347/root/chroot_tmpdir/scmroot/R-flexiblas
Cloning into '/var/lib/mock/f45-build-6205-347/root/chroot_tmpdir/scmroot/R-flexiblas'...
$ git fetch origin abc5ec1e81235b77e2f461f3f8aba3b3d4a8345a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-flexiblas
 * [new ref]         abc5ec1e81235b77e2f461f3f8aba3b3d4a8345a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at abc5ec1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild