gh pr list --repo microsoft/vscode --state merged --limit 1000 --json author,mergedAt,title

Then you can do:

jq -r '.[] | [.author.login, .author.name] | @tsv' 1kprs.json | sort | uniq -c | sort -nr

And see there's only 63 authors and > 90% of the merged PRs are from Microsoft (which.. fair, it's their product).

I think the signal is strong enough that you can legitimately reach the same conclusion by mk 1 eyeball.

NOTE: I'm not criticising, it's a Microsoft-driven project and I am fine with that. The _do_ merge things from "random" contributors (yay) but they are overwhelmingly things that a) fix a bug while b) being less than 5 lines of code. If that is your desired contribution then things will go well for you and arguably they do well at accepting such. But they are very unlikely to accept a complex or interesting new feature from an outsider. All of this is seems totally reasonable and expected.