There was a time when people discovered a lot of text renderers break down with lots of stacked combining characters, and people were posting strings to HN that

There was a time when people discovered a lot of text renderers break down with lots of stacked combining characters, and people were posting strings to HN that IIRC either drew a stack of accents all the way up and down the page, or crashed the browser. Maybe that has something to do with the character range limits. Not all non-ASCII is forbidden, though: Français should work AFAIK, and I've seen Chinese and Japanese.