$ git clone -n https://src.fedoraproject.org/rpms/R-gsl.git /var/lib/mock/f41-build-side-1-2630785-25616/root/chroot_tmpdir/scmroot/R-gsl
Cloning into '/var/lib/mock/f41-build-side-1-2630785-25616/root/chroot_tmpdir/scmroot/R-gsl'...
$ git fetch origin 2b25c1934124386099caed350c421cc35e99b5ea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-gsl
 * [new ref]         2b25c1934124386099caed350c421cc35e99b5ea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b25c19 convert GPLv3 license to SPDX