Assuming this is a Show HN thread, cool stuff! Consider using IBM CP437 or Braille instead of periods in the hex editor. I talk about it here on my web page. https://justine.lol/braille/ It's hard to truly understand binary without a binary alphabet.
I am finding the choice of braille characters confusing: I would have assumed that one would use the 8 dots to represent the 8 bits, and that seems to be happening for the very high values--like 0xfX--but then 0x81 should have two dots... what is the logic? (I did verify that Unicode seems to have a "full set", as I could have seen them deciding to only encode ones that were "used" or something, and maybe braille had been designed explicitly to be readable upside down or something and so only used half the options, but I found a chart mapping the characters for all 256.)
It's not a Show HN, Kaitai is pretty well established and used pretty widely. Lots of people behind it, and it gets posted here periodically. It's also open source, you could open an issue with them. They're pretty receptive to ideas, given my limited experience with them.
Works fine on Firefox on Win10 for me. Might have something to do with Let's Encrypt. I'll have a chance to poke into max length and server logs a week from now. Thanks for letting me know!