This test is a safety check, ensuring that all `@NgModule`'s exported by Angular framework packages can be imported in user code without causing any build errors. Occasionally, an `@NgModule` might re-export another module. This is fine, but there are cases, especially with relative imports being used, where the compiler (in consuming projects) is not able to find a working import to these re-exported symbols. The re-exported symbols simply need to be re-exported from the entry-point. For more details on this, see: https://github.com/angular/components/pull/30667.