Alternatively it doesn't care at all. I mean, it may not even try to check the incoming encoding or do anything with it and you'd still get the right result if your browser behaves in a sane way (that is sends utf form contents to this site). It's just some bytes after all.
But I don't know the arc internals - does it do anything interesting with unicode?
Dunno, the public releases are usually behind HN anyway. I'm just going off some old (really old) pg quotes where he just said Arc only did ASCII, because he didn't care about text encodings that much. The question is why HN is somehow sending the right text encoding headers.
But I don't know the arc internals - does it do anything interesting with unicode?