A composer.json file that contains the list of components and their dependencies makes up a metapackage. Metapackage acts as the root package when many packages are used in a Magento application's extensions. As a result, metapackage will manage these packages collectively.  A package of your extension should be created by performing a zip operation on the directory with your extension. To package a component:  Create a Magento Composer file (composer.json)  Register the component using registration.php  Package and publish your component.