Yeah, that's exactly what it is. Most Web UIs that implement pull requests though only support Pull Requests between repositories hosted on their platform. You

Yeah, that's exactly what it is. Most Web UIs that implement pull requests though only support Pull Requests between repositories hosted on their platform. You can't just provide a url to an arbitrary git repo to pull from. In principle though, there's no reason they _couldn't_ implement a feature which would allow that.