You can find a list of the the accessibility rules that the Accessibility Checker checks for in this document:
How do I use the Accessibility Checker in the Rich Content Editor as an instructor?
Up front, I think it is important to note that the accessibility checker does not claim to do any kind of comprehensive check of WCAG 2.0 or 2.1 guidelines. It is only checking for a few rules. However, as I look over that list of rules, I don't recognize any of them that include the new additions from 2.1.
Of note, Canvas has open-sourced the accessibility checker:
https://community.canvaslms.com/groups/accessibility/blog/2018/06/14/the-accessibility-checker-has-b...
So in theory some of those additional checks could be added that way - I'm not sure how much active development is happening on the tool right now.
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.