[hyperchase]

Pull-request makes sense in Github, because the typical work-flow for open-source on Github is to fork the repo you want to contribute to. Hence, the maintainer has to pull the code from you.

Merge-request makes more sense in Gitlab because they're main use-case is as a self-hosted internal tool where developers most-likely are pushing all of their feature branches to a central repository and asking for the branch to be merged into the mainline branch.