Even if your open source code is on GitLab they can still be used to train Copilot. Most permissive license allows you to train AI models using them. Any licens

Even if your open source code is on GitLab they can still be used to train Copilot. Most permissive license allows you to train AI models using them. Any license that forbids AI training would not be considered "open source" under most definitions. Being on GitHub just makes it easier for them as they don't need to manually clone it from a different service.