dijit is the package that contains the widget library for Dojo Toolkit. It requires the core of the Dojo Toolkit and provides a framework for building additional widgets as well as a full set of rich user interface widgets including form, layout and data-aware items.
While still being maintained, new development is primarily focused on modern Dojo.
Checkout the Dojo framework website or if you want a more detailed technical status and overview, checkout the Dojo roadmap.
Installation instructions are available at dojotoolkit.org/download.
If you are starting out with Dojo and Dijit, the following resources are available to you:
The Dojo Toolkit (including this package) is dual licensed under BSD 3-Clause and AFL. For more information on the license please see the License Information. The Dojo Toolkit is Copyright (c) 2005-2018, The JS Foundation. All rights reserved.