Ask HN: Who is the legendary linux@horizon.com on the LKML?

A while ago, a friend pointed out some of the kernel contributions of someone only known by their email address "linux@horizon.com" (and sometimes .net)

Among their notable contributions was this improvement to the SHA1 function in PPC assembly... developed without access to the hardware. "It assembles, but I can't test it." http://www.gelato.unsw.edu.au/archives/git/0504/1753.html

Amusingly, some google searching will uncover the name "George Spelvin"... which turns out to be a classical pseudonym. Of course

So, HN, what are your fan or conspiracy theories of who, or what, linux@horizon.com is?