Certain pages that use YUI trees in Moodle fail to validate because an invalid HTML attribute called yuiconfig is used in LI tags. Although I am only reporting it here for the Assignment module, the issue exists in the following sections of code:
The markup be written in such a way that the HTML code pass W3C HTML validation.
Steps to Reproduce
1) Create an assignment activity in a course.
2) Upload a file on the assignment page.
3) Notice that the HTML contains code similar to the following:
... which was generated by Moodle PHP code similar to the following:
$result .= '<li yuiConfig=\'' . json_encode($yuiconfig) . '\'>'
WCAG 2.0 4.1.1 - Parsing
G134: Validating Web pages