Chak Nanga started the Mozilla Runtime Environment (MRE) project. Similar to a Java runtime the Mozilla runtime allows stand-alone Mozilla apps to share the core libraries sparing you from bundling the Mozilla runtime with every Mozilla app.

The Mozilla runtime includes the following libraries and services: Core XPCOM Libraries, NSPR Libraries, DOM, Caps, Docshell, Editor, Jar Support, Profile Support, Session History, XPConnect JavaScript Engine, Java LiveConnect, Accessibility, Embedding Support, Layout, Preferences Support, PSM and Wallet, L10N/I18N Support, XML Image Decoding Libraries, NGLayout (gkgfx.dll, gkgfxwin.dll etc.), Appshell, Cookies, Find Functionality, Necko, Plugin Support, RDF, URI Loader

Full story at http://www.mozilla.org/projects/embedding/MRE.html