0install 

Zero Install management of implementation caches, digital signatures, etc.

Zero Install services for solving dependencies, downloading implementations, executing apps, etc.

Utilities for creating and modifying Zero Install feed files

Zero Install data model for the feed format

Zero Install methods for integrating applications with desktop environments (creating menu entries, etc.).

Zero Install interfaces/abstractions for types from ZeroInstall.Services package

Command-line interface for Zero Install (both an actual CLI and a library for building other clients)