Please add an option to switch to xxd for input or output, and possibly add some form of indication of non-printables or bad UTF-8 (like Clang's warnings which do <U+XXXX> in reverse color).

When creating an PPCG submission, I think using kbd tags in a pre code block is clear enough to indicate that it is supposed to represent a raw byte.

Another idea: incorporate codepage language bars into TIO

So like abrudz/lb, but incorporated into TIO. This is going to ease the programming of a lot of SBCS language programmers who use TIO.

Yes. Another thing is that it is physically impossible on Windows to copy/paste a null byte, and a raw null byte is often very useful.