The package provides a high-level interface for producing document-level commands. In that way, it offers a replacement for LaTeX 2e's \newcommand macro, with significantly improved functionality.

The package on CTAN derives from a snapshot of the LaTeX 3 repository, taken on 2015-09-11, and is distributed as part of the l3packages bundle.

The author is The LaTeX Team. The package is Copyright © 2009-2016 LaTeX3 Project.