$ git clone -n https://src.fedoraproject.org/rpms/libtommath.git /var/lib/mock/f45-build-17142-496/root/chroot_tmpdir/scmroot/libtommath
Cloning into '/var/lib/mock/f45-build-17142-496/root/chroot_tmpdir/scmroot/libtommath'...
$ git fetch origin 0fe13b872ba0caa076b696842128009d9ff2b42d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtommath
 * [new ref]         0fe13b872ba0caa076b696842128009d9ff2b42d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0fe13b8 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild