https://wp.jochen.hayek.name/blog-en/2017/12/20/editing-a-file-living-in-a-gitlab-repository-within-a-browser-window-edit-file-trying-to-display-the-changes-between-the-working-version-and-the-last-committed-one/
editing a file living in a GitLab repository within a browser window ("Edit File"), trying to display the changes between the working version and the last committed one