We recently had a request from a client asking about the possibilities of allowing students to perform self-grading within the assignment and forum activities, particularly using Rubrics.

This has also been discussed a few times in the forums:
https://moodle.org/mod/forum/discuss.php?d=227293
https://moodle.org/mod/forum/discuss.php?d=214494

Adding this tracker issue to help gauge the interest on having this feature.

I think this could also combine (in future) with some form of peer-assessment grading as well.