$ git clone -n https://src.fedoraproject.org/rpms/R-gsl /var/lib/mock/f39-build-1587542-38222/root/chroot_tmpdir/scmroot/R-gsl
Cloning into '/var/lib/mock/f39-build-1587542-38222/root/chroot_tmpdir/scmroot/R-gsl'...
$ git fetch origin 21ad8345647902ce7c2f19a05e2ca54f059d7841:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-gsl
 * [new ref]         21ad8345647902ce7c2f19a05e2ca54f059d7841 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 21ad834 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild