You can remove the “.. XXX” line; I understand it is just like a TODO comment, and with this fixed it would no longer be relevant. I suggest putting the links next to the sentence that ends “. . . the encoding name must be recognized by Python.”

The links should be internal links, rather than hard-coded Internet links to another version of the documentation. See <https://docs.python.org/devguide/documenting.html#cross-linking-markup>. The Standard Encodings section already has a label already set up for you to use :)