With the GitHub PR Builder Plugin, is it possible to comment on a PR from an upstream repository?

To start, we have been enjoying the GitHub PR Builder Plugin for quite a while with normal use, so all repos in question are set up for Jenkins to interact. In this case, we have an upstream pipeline that’s triggered by PRs, and we have a downstream pipeline that runs a bunch of tests. We already extract information from the upstream logs like commit hash and the PR URL, so what I’m after is having the downstream pipeline comment on the upstream PR. Obviously, I can’t use the plugin conventionally for this, so is there a way I can somehow use the API?

I couldn’t find anything googling. But you can use GitHub - cli/cli: GitHub’s official command line tool with the same credentials (i think it auto accepts GITHUB_TOKEN) to post comments on any issue/pr/etc