I was curious how UTF-8 was converting a sequence of bytes to a code point that wasn't obviously related to the values of those bytes. With the help of UTF-8#Examples, here is how %C3%A9 (é) is converted to the code point 233. The bits for %C3 and %A9 are 11000011 and 10101001 (195 and 169). The first 4 bits of the first byte tells how many bytes are used for this character. In this case the first 110 means two bytes are used (1110 would mean 3 bytes etc). For two byte encodings the last 5 bits of the first byte are used for the higher order bits of the code point so (00011). The leading 1 and 0 bits (10) of the second byte are used to indicate that this is a continuation byte. The rest (101001) is used for the code point. So we end up with 00011 101001; printf "%s\n", 0b00011101001 gives 233.