I can't find any requests made by user agent `actions-runner-controller` in GitHub.com's telemetry in the past 7 days.
Turns out we only set user agent `actions-runner-controller` if we are configured to use BasicAuth which is not the case for most customers I think.
I update the code a little bit to make sure it always set `actions-runner-controller` as UserAgent for the GitHub HttpClient in ARC.
A further step would be somehow baking the ARC release version into the UserAgent as well.