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[binaryberry]

Thanks Tijmen! I had originally considered that approach but in the wrong way: I was getting a list of all alphagov repos (there are A LOT), then iterating over them to get open PRs, hence it was a lot of requests and it was very slow (that's when I decided to add the list of repos, which I realised wasn't ideal).
Your way sounds like it might be much better as it's only one request, not one request to get the list of repos + one request per repo, which is a lot. I see at the minute there are 133 open PRs so that shouldn't be too long. Happy to take a pull request if you want to do it, and if not I'll make that improvement over the Christmas holidays. Thanks for the very good idea.