https://docs.sourcegraph.com/getting-started/github-vs-sourcegraph#searching-repositories-branches-and-forks https://docs.sourcegraph.com/getting-started/github

https://docs.sourcegraph.com/getting-started/github-vs-sourcegraph#searching-repositories-branches-and-forks https://docs.sourcegraph.com/getting-started/github-vs-sourc... highlights just such a comparison, and they have both "fork:yes" and "fork:only" and their "rev:" keyword supports branch globs