Test262 is another test suite for JavaScript. It provides a number of very detailed set of around 20k tests and aims to test every line in the specification, going into some details which the current compat table omits. However, there is not currently a place where test262 scores are surfaced, and test262 does not include categorization into features, weighting, or a pretty website.

For me as an implementer, test262 has been extremely useful in identifying non-compliant parts of V8 so that we can fix them. Although many of the bugs don't reflect something that seems likely for a user to run into, it feels to me like a good tool for making a JavaScript implementation into a reliable, consistent surface.

Maybe it would be useful for others as well to see in a comparison context. I'm wondering whether it might make sense to have one item in the compat table here be for the entire test262 score. It could be factored into the overall score, or left to the side for independent reference. Thoughts?