Join GitHub today
GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.Sign up
That said, great question, important question.
I believe utterances is GDPR compliant because the utterances widget does not store any data at all. No user data, no comment data, nothing. Everything is stored in the GitHub issues and comments.
There is google analytics on the utterances on the home page only. There is no tracking whatsoever on the widget that you include on your blog pages.
I will check with some experts on my team @MicrosoftDocs- we're using a similar GitHub issues based feedback system on https://docs.microsoft.com. To my knowledge it is GDPR compliant. I don't know of any material implementation differences that would impact GDPR.
Here are a couple links related to GitHub's GDPR compliance: