$ git clone -n https://src.fedoraproject.org/rpms/stdx-allocator.git /var/lib/mock/f31-build-73972-31057/root/chroot_tmpdir/scmroot/stdx-allocator
Cloning into '/var/lib/mock/f31-build-73972-31057/root/chroot_tmpdir/scmroot/stdx-allocator'...
$ git reset --hard 3229f29d1790d8c3a0aa36cda438e3de83efb6c1
HEAD is now at 3229f29 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild