Not for PRs or issues though which are arguably the biggest reasons to use GitHub. Still this is definitely an improvement.
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As for PRs: I'm sure Mozilla welcome contributions, but accepting GitHub PRs is going to be a recipe for thousands of low-value drive-by commits, which will require a lot of triage.
I agree it is rather basic but I don't see how it's hard to navigate.
> accepting GitHub PRs is going to be a recipe for thousands of low-value drive-by commits, which will require a lot of triage.
I don't think that really happens based on what I've seen of other huge projects on GitHub.