> Are you saying we'll increase the diversity of checks all over the place,
> increasing confusion, increasing requirements?

The idea was to align mtree with other base tools already supporting SHA-512.
I wasn't suggesting making it a default or intending to add unnecessary
complexity, just providing the option for when it might be suitable.

> Are you saying it performs significantly poorer on other machines?

I've seen SHA-512 perform better on 64-bit systems, but I'm not claiming 
it's better everywhere. Just noting a case where it was useful for me 
and potentially others. I only meant it can be faster in certain contexts,
not that it's universally better.

> I think nothing needs it.  I'm personally waiting for SHA1024 because it
is twice as good as SHA512.

I'm not saying 'bigger is better' or suggesting it is 'twice as good' but 
simply offering the option for an existing and sometimes faster one.

I understand that it's not welcome, thanks for the feedback and for taking
the time to consider nonetheless.