It's certainly Google Cloud branded, but it appears to have somewhat equivalent functionality to Github.

For Google to launch something purely as a "Github competitor" would be silly because those using Github would quickly dismiss it; "we already have Github!"

So Google are playing up the integration with the rest of Google Cloud, integrating with Github and Bitbucket, and offering additional features.

You have to extrapolate a bit to realize it, and Google probably won't admit it, but this is definitely intended as a Github/Bitbucket competitor.