$ git clone -n https://src.fedoraproject.org/rpms/R-gmp.git /var/lib/mock/f39-build-1470527-33902/root/chroot_tmpdir/scmroot/R-gmp
Cloning into '/var/lib/mock/f39-build-1470527-33902/root/chroot_tmpdir/scmroot/R-gmp'...
$ git fetch origin 9970fc9bdec1753e04569b6a744fd147d6a4721d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-gmp
 * [new ref]         9970fc9bdec1753e04569b6a744fd147d6a4721d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9970fc9 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild