Extension Analyzer is an Extension to Visual Studio 2010 that allows browsing several extensibility entities inside of Visual Studio. It also allows diagnosing several common errors loading extensions by reporting information from logging services inside Visual Studio.
"The Extensibility team in VS has recently added several exciting features to Extension Analyzer. In addition to browsing through VS Packages and MEF Extensions, it's now possible to browse through the collection of VSIX extensions and PkgDef files installed on the machine. The tool scans the contents of VSIX extensions and PkgDef files and establishes relationships between VS Packages, VSIX extensions, PkgDef files and MEF Components. These relationships allow navigation between the different entities."
Download: Extension Analyzer