saw someone complain that character encoding is poorly defined in bencode... weird complaint given that bencode's string type is literally called "byte string". it stores bytes, not characters.
the whole point is that they DON'T specify a character encoding because if you want to encode characters then you make that a part of your own thing's spec. bencode is a data structure format that you extend for your own purposes - it doesn't impose on how your content is formatted, only how the structure is formatted.