[html] Issue: Define or remove the use of the term Plain Unicode String marked as i18n

r12a has just labeled an issue for https://github.com/w3c/html as 
"i18n":

== Define or remove the use of the term Plain Unicode String ==
5.7.2 The drag data store
http://www.w3.org/TR/html51/editing.html#the-drag-data-store

The drag data store introduces a new term called "Plain Unicode 
String". It is unclear if this type of string has a restricted set of 
characters. The spec seems to imply that this is simply text. If this 
term is equivalent to Unicode text or strings, then we should use 
either one of those terms rather than introducing a new term. 
Additionally, what about a binary string that contains a file name as 
per the drag item kind.

See https://github.com/w3c/html/issues/476