The SourceForge sync tool appears to only include release syncing as far as I can tell (the wording is ambiguous and the docs only mention import, not active sync, so I'm not sure what they provide?).
For what it's worth, GitLab does have import tools in CE[2]. You can also use repository mirroring (along with any other Enterprise Edition features) if you're an open source project on GitLab.com.
[0]: https://gitlab.com/gitlab-org/gitlab-ce/issues/18732 [1]: https://gitlab.com/gitlab-org/gitlab-ce/issues/18732#note_47... [2]: https://docs.gitlab.com/ee/user/project/import/github.html