|  | # Legacy components | 
|  |  | 
|  | This section contains documentation about components using the legacy component | 
|  | framework ([Components v1][glossary.components-v1]) implemented by `appmgr`. | 
|  | The Fuchsia platform team is currently [migrating legacy components][migration] | 
|  | to the modern component framework ([Components v2][glossary.components-v2]). | 
|  |  | 
|  | Note: New component development should use the modern component framework. | 
|  | For more details, see the [Components overview][components-overview]. | 
|  |  | 
|  | ## Architectural concepts | 
|  |  | 
|  | - [sysmgr](sysmgr.md): The component responsible for hosting the `sys` realm. | 
|  |  | 
|  | ## Developing components | 
|  |  | 
|  | - [Component manifests](component_manifests.md): Declaring legacy components. | 
|  |  | 
|  | ## Debugging and troubleshooting | 
|  |  | 
|  | - [Hub](hub.md): A portal for introspection of `appmgr` components. | 
|  |  | 
|  | ## Testing | 
|  |  | 
|  | - [Test components][test-component]: Implementing component tests with the | 
|  | legacy component framework. | 
|  |  | 
|  | [components-overview]: /docs/concepts/components/v2/introduction.md | 
|  | [glossary.components-v1]: /docs/glossary/README.md#components-v1 | 
|  | [glossary.components-v2]: /docs/glossary/README.md#components-v2 | 
|  | [migration]: /docs/contribute/open_projects/components/migration.md | 
|  | [test-component]: /docs/concepts/testing/v1_test_component.md |