Guys, introduced by @graycrow in Aurelia-cli (RequireJS): move node_modules to upper directory
It looks like yarn workspaces is a great fit for core modules development.
Keep core modules repos and dev app repo under same workspaces, it will ensure the dev app uses your local core modules code.
This works if your dev app uses webpack. cli+requirejs has issue to support parent folder node_modules currently (this issue is now fixed in auto-tracing version of cli) .