GitLab is used only for code review, issue tracking and project management. Canonical locations for source code are still https://gitweb.torproject.org/ https://git.torproject.org/ and git-rw.torproject.org.
The links on https://metrics.torproject.org/collector.html are broken and return 500 errors. (example broken link: https://metrics.torproject.org/collector/recent/)
It looks like the data is still available over at https://collector.torproject.org/