JOSM MapCSS validator rules for warning users about bad edits before uploading, and suggesting automatic fixes for them.
File - Edit - Preferences - Data validator (blue checkmark) - Tag Checker Rules - Click the blue +-sign on the right
Add this as URL:
https://raw.githubusercontent.com/osmno/josm-validation/master/project-norway-rules.validator.mapcss
and name it something like "Project Norway".