For me to practically consider switching from Github, the browser plugin Octolinker would need to support Gitlab. https://octolinker.now.sh/
I’ve gotten so used to reading code in my browser, thanks to Octolinker, it would be a huge setback to work with a repository where I couldn’t quickly view imported code online by clicking on the import statements.
The maintainer is open to PRs, this is a thing you can change! https://github.com/OctoLinker/OctoLinker/issues/113