Just a quick hack to be able to check the mergability of two branches ...
$ npx merge-conflicts origin/feature/whatever origin/stable
CONFLICT base 100644 77cfa58d94e8e06a2d2500468fff6f86ea820876 composer.json
CONFLICT base 100644 640c614c8fcf697086c0e7ed3775a32da1758ada composer.lock