They have a couple, neither are usable by Cloud customers. I believe the git integration is for Stackdriver Debugger (debug stuff in prod with viewing source), and container builder[0].

As for issue trackers, there is the chromium one that is based off of the old Google code issue tracker [1]. And about a year ago they started exposing a newer issue tracker[2].

[0] https://cloud.google.com/container-builder/

[1] https://bugs.chromium.org/p/project-zero/issues/list

[2] https://issuetracker.google.com/issues?q=status:open

I feel like there is an opportunity here for them to provide a CitC as a service type thing.

AFAIK, no.

Heck, Chrome and Android both use (separate) in-house ones.