Not very many people are interested in it because they don’t use emacs.
Either way, if you want Emacs plugin support or whatever, you would be better to open an issue here so that the Devs can see how many people are interested, and then they can see that people want it and spend time developing something: Issues · GitLab.org / GitLab · GitLab
Until someone like you opens an issue, no such support will happen. The more people that vote on the issue to show interest means more chance of it being supported sometime in the future. Nobody has done that so far, so not surprising that it doesn’t exist.