A package is a container that stores various types of features or assets, such as:
Packages deliver a wide range of enhancements to Unity through the Package Manager. In the Editor, you can access the Package Manager window through this menu: Window > Package Manager.
Note: The Package Manager also supports viewing any Asset Store packages you have already downloaded or imported from the Unity Asset StoreA growing library of free and commercial assets created by Unity and members of the community. Offers a wide variety of assets, from textures, models and animations to whole project examples, tutorials and Editor extensions. More info
See in Glossary.
When Unity opens a Project, the Unity Package Manager reads the Project manifestEach Unity project has a project manifest, which acts as an entry point for the Package Manager. This file must be available in the
<project>/Packages directory. The Package Manager uses it to configure many things, including a list of dependencies for that project, as well as any package repository to query for packages. More info
See in Glossary (1) to figure out what packages to load in the Project. Then it sends a request (2) to the package registry server (3) for each package that appears as a dependencyIn the context of the Package Manager, a dependency is a specific package version (expressed in the form
package_name@package_version) that a project or another package requires in order to work. Projects and packages use the dependencies attribute in their manifests to define the set of packages they require. For projects, these are considered direct dependencies; for packages, these are indirect, or transitive, dependencies. More info
See in Glossary in the manifest. The package registry then sends the requested information and data back to the Package Manager (4), which then installs those packages (5) in the Project. Each Project has its own manifest which lists the packages to load as “dependencies” of the Project.
If you want to include a package in your Project, you must update the Project manifest to include it in the list of dependencies. If you want to, you can modify the Project manifest directly, but it is safer and easier to let the Package Manager do that. For more information on using the user interface, see the documentation for the Package Manager window.
The Package Manager uses three interfaces to communicate with users, manifests, and registries:
|Interface method||How to work with it|
|User interface||You can use the Package Manager window to quickly browse and search for features. It also allows you to easily select the packages you want to install and update, and resolve conflicts in package dependencies. The Package Manager provides a user interface in order to make changes to the Project manifest directly.|
|Package manifestEach package has a manifest, which provides information about the package to the Package Manager. The manifest contains information such as the name of the package, its version, a description for users, dependencies on other packages (if any), and other details. More info
See in Glossary
|The Package Manager provides a dedicated Inspector in Unity, which allows you to view the manifestThere are two types of manifest files: project manifests and package manifests.
See in Glossary of any package, while the manifest gets the main focus in the Project view at the same time. This integration means you can also edit package manifests directly in Unity for embedded or local packages.
|Scripting API||The Package Manager scripting API enables users to interact with the Package Manager programmatically. You can use it to query the package registry, install, embed, and remove packages, and list packages using a variety of criteria.|