https://docs.gitlab.com/ee/api/project_import_export.html https://docs.gitlab.com/ee/user/project/settings/import_expo...
But seriously: I can only imagine how many hours each individual has put in writing all these messages on github. Some pull requests and issues read like full blog posts, and oftentimes we reference them in the source code. So it would really be a shame if they got lost.
People are giving so much of their data into third party hands these days without ever thinking about it. We want to be in control of our own data, and while hosting a gitlab instance by ourselves is not feasible for us at this point, having a good backup strategy would already be a big improvement in that direction.