the repository description (GitLab 7.7+)

the Git repository data (GitLab 7.7+)

the issues (GitLab 7.7+)

the pull requests (GitLab 8.4+)

the wiki pages (GitLab 8.4+)

the milestones (GitLab 8.7+)

the labels (GitLab 8.7+)

the release note descriptions (GitLab 8.12+)

the references to pull requests and issues are preserved (GitLab 8.7+)

https://docs.gitlab.com/ce/workflow/importing/import_project...