When you're creating or editing a project, LinkApi will request for the files in your Catalog that you want to use in that project. That's what we call Dependencies. They're a shortcut from your Catalog to your project. If you edit a App inside your Catalog and add a new Resource, it will update in all of your projects.
Selected Dependencies at the creation of a Project
You can select Private Apps, Universal Apps and Functions from your Catalog. If you update a private App from your Catalog, all your projects using that file will be updated as well.
You can also add dependencies after a project is created. Inside the Code Builder, click to Manage the Dependencies.