$ git clone -n https://src.fedoraproject.org/rpms/mathomatic.git /var/lib/mock/f45-build-18113-508/root/chroot_tmpdir/scmroot/mathomatic
Cloning into '/var/lib/mock/f45-build-18113-508/root/chroot_tmpdir/scmroot/mathomatic'...
$ git fetch origin 2b096d0befaadee37a789d39730e25c6763ceec2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mathomatic
 * [new ref]         2b096d0befaadee37a789d39730e25c6763ceec2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b096d0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild