WTF-8 is a superset of UTF-8 that allows unpaired surrogates.

From ES6 6.1.4, "The String Type":

If we try to encode these ill-formed code units into UTF-8, we similarly
get ill-formed UTF-8. WTF-8 is a fun name for that encoding.

https://simonsapin.github.io/wtf-8/

License

ocaml-wtf8 is MIT licensed, as found in the LICENSE file.