this was discussed in the recent 1.11 Retro part 2 meeting:
https://youtu.be/sZekfvgIx28?list=WL&t=2076

me and @BenTheElder had a discussion about this today on slack:
https://kubernetes.slack.com/archives/C2C40FMNF/p1530819530000300
RAW copy-pasta of the discussion:
https://gist.github.com/neolit123/00835a9eec63de997329f0edf83977f6

also @dims proposed this tutorial about writing an Slack app.
https://github.com/slackapi/Slack-Python-Onboarding-Tutorial

The idea here is that sig-release need a tool to be able to find the email and/or slack handle of a user that submitted a PR, in case they need to directly contact said user about a certain PR related action.

one potential way of doing this is over a "slack-app", which is like a bot, except it has more power of what it can do. querying the slack app in the lines of give-me-email-and-slack-of <github-handle> or give-me-details-about-this-pr <PR#> would supposedly result into the app cloning the github repo and extracting email details for this committer. then it would also try to match the email used for the commit to the email used for the slack registration.

one big pitfall here is if the user has decided to set a dummy email in his git config user.email, which is not that uncommon.

right now, one reliable but manual way of finding the email of a member is by going here:
https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!forum/kubernetes-membership

searching for a github handle or a individual name and clicking over a user email and saying "i'm not a robot".

as suggested by Ben, i'm opening this is issue in k/community for a discussion about the options we have. possibly the implementation itself would go in k/test-infra.

/help
/kind feature
/cc @tpepper @jberkus
/cc @kubernetes/sig-testing-feature-requests
/cc @kubernetes/sig-release-feature-requests