AFAIU the number was picked to protect against CVE-2017-12842 covertly.
See: https://github.com/bitcoin/bitcoin/pull/16885
<https://github.com/bitcoin/bitcoin/pull/16885/files> which updated the
text to explicitly mention this fact.

On Sat, May 23, 2020 at 11:20 AM Thomas Voegtlin via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Hello list,
>
> I have been trying to CPFP a transaction using OP_RETURN, because the
> remaining output value would have been lower than the dust threshold.
>
> The scriptPubkey of the output was OP_RETURN + OP_0, and there was a
> single p2wsh input.
>
> The result is a 60 bytes transaction (without witness), that gets
> rejected because it is lower than MIN_STANDARD_TX_NONWITNESS_SIZE, which
> is equal to 82 bytes.
>
> Why is that value so high? Would it make sense to lower it to 60?
>
>
> Thomas
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>