Not necessarily though, as filenames aren't required to be valid strings, so that would break json syntax. And json doesn't have a syntax for "just a blob of by

Not necessarily though, as filenames aren't required to be valid strings, so that would break json syntax. And json doesn't have a syntax for "just a blob of bytes", besides the fact that wrapping bytes in text just to be decoded back to bytes seems silly to me, but that's an opinion