$ git clone -n https://src.fedoraproject.org/rpms/sagemath.git /var/lib/mock/f38-build-side-42-init-devel-957775-28787/root/chroot_tmpdir/scmroot/sagemath
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-957775-28787/root/chroot_tmpdir/scmroot/sagemath'...
$ git fetch origin d510b9edacdae0dfcca44134a0839472bf30caf6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sagemath
 * [new ref]         d510b9edacdae0dfcca44134a0839472bf30caf6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d510b9e Version 9.8