Infobox type attribute bug

The new  attribute on   tags does not replace space  characters with hyphen-minus  characters, unlike the corresponding   and   attributes. Because the HTML  attribute takes a set of space-separated tokens, this allows users to install any class they please on an infobox, potentially harming portability and accessibility.

Infobox source
 Inspect me!

Expected result
An infobox with the following custom classes, in addition to the standard ones:



Actual result
An infobox with the following custom classes, in addition to the standard ones: