HTML data attributes not accepted

[tagawa]

Problem:
HTML data attributes are not accepted by the sanitizer and are therefore being stripped.

Example:
This feed uses multiple data attributes in each item's HTML content:
https://thewatchsite.com/forums/the-japanese-watch-discussion-forum.21/index.rss

Requested action:
Please could you add data attributes to the list of accepted HTML attributes? They are valid if the attribute name starts with data- and has at least one character after the hyphen.

For reference:

• W3C HTML specification
• Data attribute examples