The functionality of WS has not changed since Implementation
This encoding is similar to URIComponent encoding.
The Sec-WebSocket-Protocol header contains protocols. Protocol values have a character set. This encoding is used when TompHTTP requires characters outside this range in protocols.
Each character in a string is checked to see if it's in the character set or a reserved character.
The character is replaced with an escaped value if this condition is met. An escaped value is a percent symbol (0x37, ASCII) followed by the characters hexadecimal code. For example, the string 1/100% would become 1%2F100%25.
Each character in a string is iterated over. If the character begins with %, the following two characters are assumed to be hexadecimal codes. The hexadecimal will be read, followed by the % symbol, and the next 2 characters are replaced with the character belonging to the hexadecimal code.
%
!#$%&'*+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ^_\abcdefghijklmnopqrstuvwxyz|~
ASCII characters. 77 Total.